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Scanned by CamScannerSection \
MathematicsSets and Cartesian Product of Sets
1 Set
In our mathematical language, everything in this universe
whether living or non-living is ealled an object.
If we consider a collection of objects given in such a way
that itis possible to tell beyond doubt, whether a given object
is in the collection under consideration or not, then such a
collection of objects is called a well-defined collection of
objects.
(a) Definition Any Collection of well defined objects is
called a set, By ‘well-defined objects’, we mean that
given a set and an object, it must be possible to
decide whether or not the dbject belongs to the set.
‘The objects in set are called its members or elements.
(b) Notations Sets are usually denoted by capital leters
A,B, C etc. and their elements by small letters a, b,
cet.
Let A’ be any set of objects and let a be a member of A,
then we write a © A and read it as ‘a belongs to A’ or ‘a is an
element of A? or ‘a is member of A’. Ifa is not an object of
Avthen we write @ ¢ A and read as ‘a does not belong to A’ or
‘as not an element of A? or ‘a is not member of A’.
e841 The collection of first five prime numbers is a set
containing the elements 2, 3, 5,7, 11.
e842 The collection of good cricket players of India és not
4a set, since the term “good player is vague and it is
not well-defined.”
1 Set Builder Form
In this method, instead of listing all elements of a set, we
‘write the set by some special property or properties satisfied
by all elements and write it a5,
‘A= (x: Pa) = (al x has the property PO)
and read it as ‘A is the set of all elements x such that x has
the property P’. The symbol *: or ‘I’ stands for ‘such tha”
eg, If A= (1.2.3.4). then we can write,
ee N:x<5)
1 Empty Set
‘A set consisting of no clement is called an empty set or
null set or void set and is denoted by the symbol or { }.
egal (xixeN,3ex<4
42 (xxeR, P+1=0=9
‘A set which has atleast one element is called a nonempty
set
The set (0) & not an empty seta it contains the element O
(0)
+ The set (6) is not a null set. tis a set connaning one element
e
| Singleton Set
A set consisting of only one element is called a singleton
set
e.g The set (3) isa singleton set.
| Finite Set
|A set in which the process of counting of elements surely
comes to an end is called a finite set
‘eg.. | Ser ofall persons on the earth.
egu2 (xixel.xisa factor of 1000)
1 Infinite set
A set which is not finite is called an infinite set. In other
words, a set in which the process of counting of elements
does not come to an end is called an infinite set
11 Set of all points in a plane.
2 (xeQ:0
yeA, then A and B
are equal.
e841 (4,8, 10} = (8,4, 10)
(The order in which the elements of a set is also
immaterial]
Scanned by CamScanner€
' 4-1 CHAPTER » Sets and Cartesian Product of Sets
en? (24,7) 12 464,72)
{re repetition of clements of sti also immaterial]
1 Equivalent Sets
‘Two finite sets A and B are said to be equivalent,
ree st so equvet bt euler ned
rot be equal
Equivalence of two sets is denoted by the symbol *~'.
“Thus if and B are equivalent sets, we write A ~ B which is
read a8 ‘A fs equivalent to B’.
egyA=(1,2,3),B= (2,35). thenn@)=3, n@)=3.
‘Since, n(A)=n(B), therefore A and B are equivalent
‘and we write A ~ B.
f
1 Subset
‘The set Bis sad to be subset of set A, if every element
of set B is also an clement of set A. Symbolically we write it
3, BoAorADB.
@ BS Ais read as B is contained in A or B is subset
of A.
Gi) AD Bis read as A contains B or B is a subset of A.
Evidently if A and B are two sets such that xe B = XA,
then Bis subset ofA, The symbol stands foe ‘implies’. We
reat sx belongs to B implies that x belongs to A.
eg, Let =(1,2,3,4} ;B=(1, 2,4).
Here, B is a subset of A,
1 Proper Subset
A set B is said to be a proper subset of set A, if every
clement of set B isan element of A whereas every element of
Ais not an clement of B.
We write it as BC A and read it as “B isa proper subset
of A’. Ths, Bis a proper subset of A, if every clement of B
isan element of A and there is atleast one element in A which
is notin B.
Observe that AG Ae, every set is a subset of itself but
not a proper subse.
egy LetA=(1,2,3}; B= (1,2), then BOA
| Power Set
‘The set formed by all the subsets of a given set A is
called the power set of , itis usually denoted by P(A),
es A= (1,23), them PCA) = (6 (1), (2), (3) 1.2),
{2,3}, (3,1), (12.39)
Some Results on Subsets
@ Every set is a subset of itself
G The empty set is a subset of every set.
Gi) The total umber of subset of infinite set containing
nn element in 2.
1 Comparable Sets
“Two sets A and B are said to be comparable, if one of them
is a subset ofthe other ie, either AS Bor BSA.
e.g The sets {1, 2,3) and (1, 2,3,4, 5} are comparable
sets.
1 Universal Set
In any discussion in set theory, there always happens 10 be
4 set that contains all the sets under consideration i., itis a
super set of each of the given sets, Such a set is called the
universal set and is denoted by U.
egufA= (24,5), B= (13,5) C= (35,710),
D= {2,4,8, 10} and U= (1, 2,3,4.5,6,7.8, 10, 1}
be the given sets. Here, the sets A, B, C, D are subsets
ofthe set U. Hence, U is a universal st.
1 Operations on Sets
‘Now, we introduce some operations on sets to construct
new seis from the given below
@ Union of sets The union of two sets A and B, denoted
by AU Bis the set of all those elements, each one of
iscither in or in Bor in both A and B.
‘Thus, AUB=(x:xeAorxe B}
Clearly, xe AUB => xeAorxe B
Ani, x€AUB= xe Aorxe B
In the figure, the shaded part represents AUB.
is evident that AC AUB, BC AUB.
eg, A= (1, 2,3) and B= (1,3, 5,7), then
AVB=[(1, 2,3, 5,7)
(@ Intersection of sets The intersection of two sets A
and B, denoted by AMBis the set of all elements,
‘common to both A and B.
Thus, AN B=(x:xe A and xe B}
Clearly, xe ANB = xeAandzeB
And, x€ANB => xeAandreB
CO)
In the figure, the shaded part represents ANB.
It is evident that ANBCA, ANB CB.
Scanned by CamScannerCHAPTER» Sets and Cartesian Product of Sets | 5
(Go. Disjoin sets TWwo sets A and B are suid tobe disjoint,
if ANB=6if ANB > then A and B are said 10 be
intersecting or overapping set. eal U = (x
1,23, 45.6), B= (7, 8,9, 10,11) and (c:xisavowel),
6,8, 10, 12,14), then A ane Bare dsfoine (2 xls consonant).
avty fig Mand Geare taerpenting 2s, 1 Some Results on Complementation
CG) ‘The following results aze the direction consequences of
the definition ofthe complement of the set.
ou
» lO ee @ Walrus zeq)=0;
difference A ~ B isthe set of all those elements of A Bete nadhfeeDniadlwtl
‘which do not belong to B, @ AY = (eeu sxe) =(re Us xe A=
Thus, A-Bs= [x:xeA mde) Gi) And alzeU xe An ed :2€A=6
Chay, £¢A~B= xed andxe B.
7 1 Laws of Algebra of Sets
GX) keno
Oe (@ AUA=A () AnA=A
entity Laws
Inthe figure, the shaded part represents A ~ B. () AUg=A © AnuU=A
‘Similarly, the difference B — A is the set of all those
elements of B that do not belong to A i.e,
sxe BandxeA)
i) Commutative Laws
@ AUB=BUA —(b) ANB=BNA
(iv) Assoctative Laws
q (@ (AUB)UC= AU(BUO)
Gs) annce anton)
z
(9) Distributive Laws
In the figure, the shaded part represents B — A. (@) AUBNO}= (ALB) (ALO)
1,3,5,7, 9} and B= (2, 3,5, 7, 1), then (0) AM(BUC)=(AN BULAN)
2, 11). ; (a) De Morgan’s Laws
(®) Symmetric difference of two sets The symmetric (@ (AUBY=A'nB’ (An By =4'UB"
difference of two sets A and B denoted by A A Bis
the set (A~B)U(B-A). s
(A-B)U(B-A) 1 Points to Remember
xix€ANB) @ n(AVB)=n(A)+n(B)
@®| Gi) (AUB)=n(A)+n(B)=n(AB)
(ii), AUB=(A-B)U(AMB)U(B- A)
a6 Gv) n(AUB)=n(A~B)+n(ANB)+n(B—A)
‘The shaded part represents A A B. (W) n(A)=n(A-B)+n(ANB)
eg. A= (1, 2, 5,7, 9} and B= (2, 3,5,7, 1)
(s)_ n(B)=n(B-A)+n(ANB)
on i (1,990 211) (vii), n(AUBUC)=n(A)+n(B)+n(C)—2(ANB)
(i) Complement ofa set Let U be the universal st and =n(BAC)=n(CNA)+N(ANBNO)
ACU, then the complement of A, denoted by A’ or (vii) Tf A, B, C are finite sets, then
U~Ais defined as A’=(x:x€U and x¢ A) n(AUBUC)=n(AOB'NC)+n(A'NBAC)
Cleat, xe’ #9 x6 A. $n(A’ AB’ C) +n(A’ABNC)+M(ANB’AC)
The shaded part represents A’. $n(AMBC) tna’ OBC’)
Scanned by CamScannerRo
"Gl CHAPTER» Sets and Cartesian Product of Sots
1 Ordered Pair
‘Two elements a and b, listed in a specified order, form an
‘ordered pair, denoted by (a, b). In an ordered pair (a,
regarded asthe first element and b the second element.
Ttis evident from the definition that
@ @b)#¢,a)
©) @.)=(6,d,ilfa=6,b=d
I Cartesian Product of Sets
Let A and B be two non-empty sets. The cartesian
product of A and B denoted by A x B is defined as the set of
all ordered paits (a,b), where a A and be B.
‘Symbolially, AXB= ((a, b);a€ A and be B)
£8 (0) Suppose A= (1,2, 3) and B= (x, y}
(0.9.42, 289.8 D)
(0, G24 3), D2. DE
Note that, if A B, then AxB# BXA,
e.g, (ii) If there are three seti A, B, Cand ae A, beB,
‘© €C, then we form an ordered triplet (a,b c).
The set of all ordered triplets (2, 6, c) is called the
cartesian product of these seis A, B and C.
te, AXBXC= (a,b,c): a€ A; BEB, c€C)
IGraph of Ax B
graph of A x Bis the st of all points in the plane
by the ordered pais of A x B.
‘Some Results on Cartesian Products of Sets
Let A and B be two non-empty subsets of R. Thea,
eguLet A =(1,2,3) B= (3,4, 5), then AxB= (1,9
(4,1, 5,3) 2,4) 2,5) G3. G.4.B,5))
0 @ Ax@UO=AxXDVAKO
() AX(BAC)=(AxB)(AXC)
( Ax@-Q=AxB)-AxO
Gi) (AKB)A(CxD)=(ANC)x(BOD)
(iy) If Ag Band CoD, then (AXC)¢ (BXD)
( If Ac Bithen AXA=(AXB)O(BXA)
(i) If A and B are non-empty subsets, then
AxB=BxA@A=B.
(vi), IFA and B are two non-empty sets having n elements in
common, then Ax B and Bx A have n? elements in
1. The set of imeligen stadents in cls is
(@) all set
(0) a singleton se
(© a fine se
(2 not a well-defined collection
2 Which ofthe following isthe empty se?
(@)_ (x: xis areal number and x7 -1=0}
SY (ins real number and ¥?+1=0)
(©) (x:.xis areal number and x? -:
(@) (e: xis a real number and x? = x42)
3. The set A={rixe R, a" =16 and 2x=6) equals
we ©) (14,3,4)
© Bb ©
4, Ifa set A has m elements, then the total number of
subsets of A is
@ nm wo
are @ rm
© 5. The number of proper subsets of the set (1, 2,3) is
o3
wv
6. “Given the ses
then AU(BAC) is
@ 6)
© (1.245)
=(4,5,6),
08 11,2.3,4)
© (1,2,3,4,5,6)
common,
Exercise i
1 i hk at
onxea|
xeR)
®) AmB
(@) None of these
xe Ryla-I21) and
AUB=R-D, then the set Dis
@ [rstexsay Y [e:1sx<2]
© [e:lsxs7 (@) None of these
9% Ifthe sets A and B are defined as
A=»): y=e%, x6 R); B=((x, y): yaa, xe Rh,
then
@ Boa ) ACB
fh Ana} @ AuB=A
10. “Let n(U)=700, n(4)= 200, n(B)=300 and
(ANB) =100, thea n(4° 05°) is equal to
@ «0 ©) 0
fF @ 0 |
Scanned by CamScanner11, In a town of 10000 families it was found that 40%
family buy newspaper A, 20% buy newspaper B and
10% families buy newspaper C, 5% families buy A and
2B, 3% buy Band Cand 4% buy A and C, 1 2% families
buy all the three newspapers, then number of families
which buy A only is
@ 3100 48) 3300
(©) 2900 (@ 1400
12, Ina city 20% of the population travels by car, 50%
travels by bus and 10% travels by both ear and bus,
Then, persons travelling by car or bus is
(@) 80% ©) 40%
ey 60% (@) 70%
13. In a class of 55 students, the number of sudents
studying different subjects are 23 in Mathematics, 24in
Physics, 19 in Chemistry, 12 in Mathematics and
Physis, 9 in Mathematics and Chemistry, 7 in Physics
and Chemistry and 4 in all the three subjects. The
numberof students who have taken exactly one subject
@ 6 9
7 BY Ail ofthese
14. IEA, B and C are aly three sets, then Ax (BU Cis
equal to
AY ARB)L(AXC) (0) ALB) XAVO
(© AXBAXC — @) Noneof these
18, IFA, B and C are any three sets, then A = (BU ©) is
equalto
A) A-BDUA-Q — &) A-B)NA-O
© @-Huc @ @-Bac
16. IfA,B and Care non-empty sets, then (A~B) U (BA)
equals
@ AuB-B @) A-anB
SS GUB-—AnB)— @ ANBDVALD
17. “If A=(2,4,5), B=(7, 89), then m(AXB) is equal to
@ 6 479
©3 @o
18, If the set A has p elements, B has q clements, then the
‘number of elements in A x Bis
@ pra (b) pegs
a] @
19. “If A=(a,6},B={ed),C=(d.e), then
{(ac).(ad),(aye),(6,e)s(b.d).(b,2)} is equal to
@ ANB UC) (0) AUBNC)
ATAKBLO) @ AxBO)
20. “Th P,Q and Rare subsets of ast A, then Rx (FU O'F
iseqyalto
(RxPORXD) MOF URKO)NRXP)
©) (RxP)U(RxQ) (d) None of these
24 Uaedensted ton themes
o) >
presen
oOo
© bexea)
22,
23.
27.
28.
29.
31.
32.
34.
35.
36.
CHAPTER « Sets and Cartesian Produet of Sets 5 7
Az (x:x x) represents
@) (0) ort)
ou) @) (2)
16 0-frca-4nhosye Wen
@ 06g Ai 160
© 260 @ 20
Which sets the subset of al given sets?
@) (1.2.3.4) () {1}
© 0) 0
Let $=(0,15,4,7). Then, the total number of subsets
of Sis
(@ 6 oy 2
© 40 (@ 20
‘The pumber of non-empy subsets ofthe set (1, 2,3, 4) is
fay 1S ~ (b) 14
“@ 16 . @17
‘The smallest set A such that A U (1,2} = (1.2,3,5.9)
is
@ (2.3.5) A) (3,5,9)
© (25,9) (@) None of these
AAB=B,then
(@) Ace DY BCA
© A=0 (@®) B=9
IFA and Bare wo ses, then AUB= AO il
@ Ace ©) BoA
AS AaB (@) None of these
Let and B be two sets, Then,
(@) AUBG AGB anc AuB
(©) ANB=AUB (d) None of these
= (Gy): y=et xe R),,
Bal(xy):y =e" xe R). Then,
BS ANB &) AnBee
© AuB=R (@) None ofthese
Hf A= (2,3,4,8,10),B={3,4,5, 10.12),
45,6, 12, 4), then (AAB)U (AMO isequlto
(3,4, 10} (b) {2,8, 10}
(©) (45,6) (@) (3,5, 14) fie
TEA and Bare any two sets, then A 6 (A.W By; equal to
aA Oy
© 4° © #
ICA, B, C be tres sets such that A UB =A U C and
ADB=ANGthen
Let =(a, b,c], B
[b,c d), C= (a,b, dhe}, them
AQ BUOis
tab, ch ©) (bad)
(0) {a b.deb @ le
IEA pm B are sets, then Am (B-ADis
° OA
OB (@) None of these
Scanned by CamScanner8 | CHAPTER « Sets and Cartesian Product of Sots
37. IrAand Bare two ses, then AM(AUBY' is equal 10
mB
4 (a) None ofthese
38. “Let U = (,2,3,4,5,6,7,8,9,10), A=(1,2,5),B=(6,7},
thea ANB’ is #
(@ B OYA
© A @s
89, IFA sany set, then .
(@) Ava" @) ava
() ANA’ * @) None of these
40. If N, =lan:ne N}, then Ny, is equal to
©», ON
ON lor,
©) Mp
41. If aN ={ax: xe N), then the set 3V.47N is
SON +) 10N
© 4N ‘ (@ None of these
42. The shaded region in the given figure is , (
@ Angug
© Aven QY
© An@-O) cA
A-BOQ
43. fA and B are two sets, then (A — B) U (B= A) U
AnBisequalto
AuB © Ans
OA @r
44. Let A and B be two sets, then {AUBYU(4’B) is
eaus)to
Ay () A
© B (@) None of these
45. Let U be the universal set and AUBUC =
((A-B)UB-C)U(C-A)F is equal to
@ AuBuc @) AUwac)
JS AnBoc @ An@uey
46. If m(A)=3, n(B)=6 and ACB. Then, the number of
elements in AUB is equal to
(3 w9
6 (@) None of these
47. “Leta and B be two sets such that
(A) =0.16, n(B)=0.14, n(AUB) =0.25
‘Then, n(A™B) is equal to
(@ 03 ©) 05
(©) 00s (@) None of these
IFA and B are disjoint, then (AUB) is equal to
(@) mA) &) me)
©) mA)+n(ey (@ n(A)-n(B)
= Then,
49.
51.
52,
53,
55.
56.
57.
58,
IEA and B ate not disjoint sets, then m(AWB) is equa)
to
(a) n(A)+n(B)
(0) n(A)+n(B)—n(AMB)
(©) mA) +n(B)+n(AB)
(a) n{A)n(B)
©) nfA)~n(B)
In a battle 70% of the combatants lost one eye, 80% aq
ear, 75% an arm, 85% a leg, lost all the four Tien
‘The minimum value of xis
@ 10 © 12
© 15 (d) None of these
Out of 800 boys in a school, 224 played crickey,
240 played hockey and 336 played basketball Of tay
total, 64 played both basketball and hockey; 80 playeg
cricket and basketball and 40 played cricket ang
hhockey; 24 played all the thee games. The number ef
boys who did not play any game is
(@ 128 () 216
(© 240 @ 160
A survey shows that 63% of the Americans like cheewe
whereas 76% like apples. If x% of the Americans like
both cheese and apples, then
@) x=39 (@) x=63
© 39
vu x isnot eal but ris real
+. No value of xis possible,
@ 7 =16 => a
2x: => xa3
‘There, is no value of x which satisfies both the
above equations. Thus, A
(c) Number of subsets of A="C, #"C, +..4°C,
(©) Number of proper subsets of the set
{1,2!3)=2?-2=6,
(b) BNC=(4), 2. AU(BNC) = (1,2,3,4}
(given)
(© Since, y=,y=-x meet when —x=
=2 x7 =-1, which does not give any real value of
Hence, ans=$ .
© Aa(x:xeR-le rel)
Ba{x:xeR:x-1S-1 of x-12 1)
= (erxeR:xS00rx22)
2 AUB=R-D, where D= (x:x€ R1Sx<2}
(© Since, y=eF and y=. do not meet for any xe R
“ AnB=6
(© mA BS) =nf(A UB)] = MU) m(AUB)
= n(U)=[n(A)+n(B)=n(A0B))
= 700 ~ [200 + 300 ~ 100] =300
(b) n(A) = 40% of 10000 = 4000
‘n(B) = 20% of 10000 = 2000
‘n(C) = 10% of 10000 = 1000
(AM B)= 5% of 10000 = 500
mB. =3% of 10000 = 300
n(C A) = 4% of 10000 = 400
(ABC) =246 of 10000 = 200
We want to find (A 0 BF 0 C)
=nlAN Bucy)
=11A)-nlA BVO!
=n(A)—nlA NB) VAN
nA) - IA 9B) +n. 0) =n B.C)
= 4000 — [500 + 400 ~ 200] = 4000-700 = 3300,
n(C)=20, n(B) = 80, (EM B)
Now, n(CUB)n(G)+ n(B) — (7B)
=20 #50 -10=60
Hence, required number of persons = 60%
©
13,
4
15.
16.
17.
18.
19.
20.
21.
22,
23.
Answer and Solutions
nt \PAO)=
We have to find n(M NPAC), n(PAM' AC),
n(CaM’oP)
Now, n(M AP'AC)=nIM A(PLCY)
(M)— nl (POO)
(M)~nf(M OP) OOD]
(M)— n(M 0 P)— n(M 0 0) + nM APOC)
-12-9+4=27-21=6
nPAM'AC)=nlPAM UO)
P)—nfP (MUO)
(P)—n(PAM)U(POC)]
nP)=n(P 0M) — WP.) +P MAO)
=24-12-744=9
nCOM'nP)
=n(C)—n(CP)=n(C OM) +n(COPAM)
=19-7-944=23-16=7
Ikis distributive law.
Itis De Morgan's law.
(-B)UB-A)=(AVB)-AOB)
AX B= (2,1), 2,8), (2,9) (4.1.4, 844.9,
575, 8),5.9)}
n(AxB) = n(A)-n(B)=3%3=9
n(AxB)= pq
BUC= (c,d) (de) = (6,4, e}
+ AXBUO=(a,b} x (6.de}
=(@, 0) (a, (a, 0), (6,0). (6.4,
Goh
(ab) Rx LOY = RAPE NON]
= RX(POQ) = (RXPIO(RXO)
= (RXQ)(RXP)
(@ Itis fundamental concept.
(b) Itis fundamental concept.
1
r0te24e wyem
yy
(b) Since,
* eam be Ge ycanbeD)
(@) Null set is the subset of all given sets.
(b) $= {0,1,5,4,7) , then total number of subsets of
Sis 2".
Hence, 232
(@) The number of non-empty subsets = 2" -1
=
(b) Given, AU(1.2)=
Hence, A
() Since, AnB=3,
Scanned by CamScanner29.
31.
32.
33.
34.
35.
36.
37.
39.
41.
(©) Let xe A= xe AUB
= re ANB
(:AcAva
(:AUB= ANB)
= xe And xeB => xe 8 AGB
Similarly, xe B=> xe A °.BCA
Now, ACB,BEA = A=B
©) AMBCACAUB 2 AnBcAUa
@ vy
> Malkeesayel
+A and B meet on(0, 1), « ANB =>
(@) AMB=2,3,4.8,10}913, 4, 5.10, 12)
= (34,10), ANC=(4)
ABN) =(,410)
(@) AQ(AUB)=A (AgBuA)
(©) Itis obvious.
(@) BUC=(a,b,6.4,¢)
1 AN(BUC)=(,b, e} Ua, Bye, dye}
esb.c}
Set, y=" will meet, when e* =
(sxe B-AS x64)
(9) An(AUBy=An(a'nB)
(oauBy = AaB]
=(ANAIMB’ (by associative law)
(®) Itis obvious.
(©) Nyy = M5
(eS and 7 are relatively prime numbers)
se N:xisa multiple of3}
[ce N :xisa multiple of 7)
[x€ is a multiple of 3 and 7}
(xe Nis a multiple of 3 and 7)
= (xe N xis amultple of 21) =21N
(2) His obvious.
(@) From Venn-Euler’s diagram,
& (A~B)UB~AYU(ANB)= AUB
(a) From Venn-Euler's diagram,
2 AUBYUA'NB) =A)
45.
46.
47.
48.
ss
51.
52.
CHAPTER « Sets and Cartesian Product of Sets 11
vol)
Sie
Clearly, ((A-B)U(B-Qu(C-AY
=ANBAC
(©) Since, AGB, -AUB=B
So, {AUB)=n(B)=6
(©) AUB)=n(A)+n(B)=n(ArB)
025=0.16+0.14—nANB)
= n(AmB)=0.30-025 = 0.05
© si
2A and B are digjoint
ANB=6
(AB) =0
(A) +n(B)—n(ANB)
-n(A)+n(B)~0 = n(A)+0(B)
(0) AUB) =n(A)+n(B)-n(A0B)
(@) Minimum value of n= 100-(30-+20+25+15)
(00-90
n(C)=224,n(#) = 240, n(B)
n(H OB) = 64, (BAC) =80
n(H AC) =40, n(COHB)=24
(CH! OB) =nl(CUHUBYT
=n(U)-n(CUH UB)
= 800-[n(C) +aC#)+n(B)—n(H 0)
=n(H 0B)=n(COB)+n(CAH OB)
=800— 224.+240+336-64-80—40-+24]
=800-640=160
(©) Let A denote the set of Americans who like cheese
and let B denote the set of Americans who like
apples.
Let population of American be 100.
‘Then, n(A)=63,n(B)=76
Now, n(AUB)=n(A)+n(B)—n( AB)
=63+76-n(ANB)
M(AUB)+0( ANB) =139
=> n(AMB)=139-n( AUB)
But n(AUB) S100
=n(AUB) 2-100"
139-n(AUB)2139-100=39
n(AMB) 239 Le, 39Sn(ANB)
Again, ANBGA ANB CB
= n(AnB)sn(A)=63
and (AB) Sn(B)=76
m1 nANB)S63
‘Then, 39< (ANB) $63 395x563
©
A)
Ai)
Scanned by CamScanner7
12 | CHAPTER » Sets and Cartesian Product of Sets
53.
54.
55.
(@) Let n(P)=Number of teachers in Physics
n((f)= Number of teachers in Maths
n(PUM)=() +n) —M(P OBE)
2=n(P)+12—4 = n(P)=12
(a) Let B, H, F denote the sets of members who are on
the basketball team, hockey team and football team
respectively.
‘Then we are given
n(B)= 2,n(H) = 26,n(F) =
nHOB)=14, nH F)=15,
nF OB) =12 and n(BOH NE) =8
We have to find n(BUH UF),
To find this, we use the formula
n(BUHUF)
=n(B)+n(H+n(F)
-2(BOH)= nH VF)~n(FB)
+n(BoHF)
Hence, n(BUH UF)
= (21+26+29)~(4415412) +8 =43,
‘Thus, these are 43 members in all,
@ n(M)=55,n(P)=67,n(M UP)=100
Now, n(M GP) =n(M)#n(P)—n(M AP)
100=55+67—n(M oP)
& n(M MP)=122-100=22
Now. (P only) =a(P)—n(M AP) =67~22=45
(© Ingeneral, AxBe BxA
AXB=BXA is true, ifA=B
(©) From De Morgan's law, (Am BY’
@ Aq
=[x:x€ Aand xe BY) = ANB
(2) Itis obvious.
(@) From De Morgan’s law,
A~(BNC)=(A-B)U(A-C)
(©) From distributive law,
ANBLO)=(ANB)UIANC)
©) A-B=(1) and B-C= (4)
(A~B)x(B-C) ={(1,4))
(@) Itis obvious
© AvB=(1, 23,8); Ane = (3)
(AVB)X(40B) =((1,3),(2,3),,3),,))
© A-B=(3},A0B=(2,5}
(4-B)x(ANB)=(6,2),8,5))
66.
67.
69.
70.
©
©
()
@
@
@
o
74.
5.
76.
@
©
(A) =4,, n(B)
N(AYen(B)xn(C) = n(AXBXC)
Araneta = neha
Given, seis ((@,)):2a* +36? =35,a,be 2)
We can see that, 2(42)* +3(43)? =35
and 2¢84)? 341)? =35
2,3), (2,3), 2, -3),(-2,3) 4, Ds =D),
1), © 4, 1) are 8 elements of the set.
n=8
obvious.
Itis obvious.
Let the original set contains (2n+1) elements, then
subsets of this set containing more than » elements,
ice, subsets containing (n+1) elements, (n+2)
elements, .. (2n-+1) elements,
+. Required number of subsets
BEC tC, MC,
C4
= CG ag,
age ig a ticg tC, 46,
Last aDyaae
= [arn] = 512
Itis obvious
(4,8,12,16,20,24,...)
6,12,18, 24, 30,..
HAC B={12,24,..)
(Malone)
= m(M)—2M AC)~n(M AP) +m PAC)
(xx is a multiple of 12)
AB
A=(ANB)U(A-B) is comect,
(3) is false.
2 (and @)aretue. —a*B 4 Nanay
nl(AxB) (Bx A))
=nl(AOB)XBOA))= m4 B)-n(Be A)
=MAMB)-n( AB) = (9999) = 992
(© MAUB)=n(A)+m(B)=n(48)=1249-4 217
Now, nl(AUB)'}=2U)—n(4U8) = 20-1723
Scanned by CamScanner1 Matrices
A rectangular arrangement of numbers in rows and
columns, is called a matrix. Such a rectangular arrangement of
uimbers is enclosed by small () or big [ } brackets. Generally
1 matrix is represented by a capital letter A, B, C, ny ete, and
its elements are represented by small lewers a, b,c, % y ete.
Following are some examples of a matrix
a(t hall Spe} ons
E=(5]
1 Order of Matrix
A matrix which has m rows and n columns is called a
matrix of order m xn and it represented By
Aan 9F A=[2j)nxn
Itis obvious to note that « matrix of order m x n contains
mn elements, Every row of such a matrix contains m elements
and every column contains m elements.
| Representation of a Matrix
‘A matrix of order m x nis generally expressed as
ay ay
ay
ay
Gait Gn yy Gm
OF A= Laylyag F= 152, ony
OF A=[Oilang F= 1,2 0M
From this representation,
a matrix Ais waiten 38 ap
clear that (i, Jth element of
CHAPTER |
Matrices and Determinan,
I Types of Matrices
(@ Row matrix If in a matrix, there is only one ro,
itis called a row matrix.
‘Thus, A = [4p iS a row matrix, if m=
‘equal to [1, 3, 5] is a row matrix of order 1 x 3.
i) Column matrix If in a matrix, there is only one colang
then it is called a column matrix.
Thus, A = [4j]joq,i8 @ column matrix, if m
1
eBoy | is column matrix of order 3 x 1.
5
Gii) Square matrix If number of rows and numbed
‘columns in a matrix are equal, then itis called a square mit
Thus, A= [4c i8 @ square matrix, if m=
is a square matrix of order 3x3
Gv) Singleton matrix If in a matrix, there is 061)
element, then itis called singleton matrix.
Thus, A = [4j]uq i8 a singleton matrix, if m=:
€-8., (4), [2], (6), [-5] are singleton matrices.
(¥) Null or zero matrix If in a matrix, all the elem
37
nmterermainy ce 6}
ig zero, then iti called a zero matrix and it is generally
Scanned by CamScannerrs, A= [alee i8 8 280 matrix, fo
for all i and j
000
ag, | 0 0 0| 188-2210 mattis of order 3x 3.
000
(vp Dingonal matrix If all elements except the principal
agonal na square MAU are zero, i is ealled a diagonal
rjus, a square matrix A = [aj] is a diagonal matr
agen
50 0
eg.{0 6 0] is. diagonal matcx of order 3 x 3, which
007,
also can be denoted by dia [5, 6, 7]
f
BS oe
(vi) Sealar matrix If all the elements ofthe diagonal of a
cigonel mati are equal, its called a scalar matix.
"Thus, a square matrix A = [ay] is scalar matrix, if
, ied
y= Ye, ia jo Where K is a constant
10 0
egq| 0-1 0| is ascalar matrix.
0 0-1
(sii) Unit matrix If all elements of principal diagonal in a
gna! mauix are 1, then itis called a nit matrix, A unit matrix
f oer is denoted by J,
“Thus, a square matrix A = [ay] is a unit mateix, if
gg), Maneolar matrix A square matix (a) is sai to be
Wangular, if each element above or below the principal
‘agonal is zero, then it is of two types.
(® Upper triangular matrix A square matrix (ay) is
called the upper triangular matrix, if ay = 0, when
i>j.
425
£8,|9 6 7) is upper triangular matrix of order 3 x 3.
O04
CHAPTER = Matrices and Determinants {147
(©) Lower triangular matrix A square matrix (ay) 58
called the lower triangular marx, if a, =O, when
isj
they are of same order and their corresponding
elements are equal ,
[i & See
(3) Singular matrix Matrix A is said to be singular
‘matrix, if its determinant [Al =0, otherwise non-singular matrix
le,
If delAl=0 => singular
and detlAl #0 => non-singular
1 Addition and Subtraction of Matrices
If A=Lo]oen and B=[2j]ayq af€ two matrices of the
‘same order, then their sum A + B is a matrix whose each
clement is the sum of corresponding element.
he, A+ B= lay + by] man
‘Similarly, their subtraction A ~ Bis defined as
A=B=[ay~bjlwer
7
go tA=|4
2
3
2| and B=
ft
746 3+2] [13 5
A+B=|4+5 2+4/=/9 6] and
243 147, 5 8.
7-6 3-2) Pat
Abe [4-5 2-4)2 [1 2
231-7] [a +
Scanned by CamScanner148 4 CHAPTER » Matrices and Determinants
Properties of Addition of Matrices
If A, B and C aze matrices of same order, then
AB=B+A (Commutative fa)
Gi) A+B)+C=A4B+O (Associative law)
Gil) A4+0= 0+ A=A, where O is zero matrix which is
audive identity ofthe matrix.
Gy A+ (CA) =0=(CA)+A, where (-A) is obtained by
changing the sign of every element of A which is
additive inverse of the matrix.
AsB=A+C]
pranceal > BE
(Cancellation law)
iy Trace (A # B) = Trace (A) * Trace (B)
1 Scalar Multiplication of Matrices
Let A= [ain BE 8 matrix and k be'a number, then the
matrix which is obtained by multiplying every element of A by
kes clled scalar multiplication of A by k and it denoted by kA.
Thus, A= [aloe =? FA= (lg
4 2 20 10
we A=\3 5),then SA=]15 25
67. 30 35,
Properties of Scalar Multiplication of Matrices
rele toca enh
Gi) (m+ mA=mA+ nA
(iii) m(nA) = (mnyA = n (mA)
mf SHI}
i
[2 nr
@L2 O42
samo (5 SHE
O-r2 O12
Vasa and ~446
- tat. b=?
“Hence, (isthe comet option,
ange 2 [lf] me off a ih then ais
@. 2
sa
saver rf]
@o 2
3-2 3a-3)_[1 30-3)
2 uis-[5p Salle
Now, by equality of two matrices, we have
a=2
ja-3=3 =
Hence, (b) is the correct option.
Example 3. 1[X and ¥are two matrices such that rr? 4
rt
ca coral ee maer
acer J}
wh) of; Jolt domes,
woe
‘subtracting Ba. i) from Bq. (we get
32] [1 2
Fel ols 4
3-1 2-2) [2 4
ocr SELL]
. rtf ‘VE |
[4 aL 2 2,
Hence, (0 is dhe correct option
Example 4 A matrix A = [aj] of order 2 x 3 whose element ot
this
23 4
Mls 4 3.
(@) None of these
Solution @y is the element of th row and th column of matrix}
& @y=14
+ @y=14283, ay =143=4
= 241=3, an
425)
+ dy #24325
“fs ahbty
Hence, (a) isthe correct option
1g “1 2] |
=|3 2]andB=| 0 s| and avB-D-?
2s a ual
(ero matris), then D matrix wit be
or
0 2
0 2
@(37 a3 Y 02
Ss. s6 OF 7) @[23
5 6 5
Example 517
o
Bn eter NT rene ere ey
Scanned by CamScanneref]
wool HEHE
a 3-2-6) fo
a [310-€ eclloo
pede StI-f
Hence, (0) isthe corect option,
132
gnample 6 I A=|2_ & 5| is @ singular matrix, then k is
vain HD
@-1 Os ©4 @-8
sotton Ais singular matic => 140
1 3
. bh & 5-0
kb 2
3 1(&= 10) 32-20) 4264-48) =0
- Tk+56=0 = k=-8
Hence, (isthe core option.
I Multiplication of Matrices
IEA and B be any two matrices, then their product AB will
‘te defined only when number of columns in A is equal to the
sunber of rows in B. If A=[4j yxy and B=[b, yep, then their
Fodut AB=C-=[,), will be matrix of order Xp , where
(AB), =
142 I
23 q{adB=|2
1
[ 144-2421 1-244-242+
* |a143-241-1 2:243-241-
[4
CHAPTER » Matrices and Determinants {149
@ Properties of Matrix Multiplication
IF A,B and C are three matrices such that their product is
defined, then
+ ABBA (Genereily not commutative)
+ (AB) C=A (BC) (Associative law)
+ IA=A= Al, where Lis identity matsix for matrix
‘multiplication.
+ A@+O=AB+AC
+) WAB=AC = B=C
(Cancellation law is not applicable)
+ IfAB=0, then it does not mean that A~=0 or B= 0,
again product of two non-zero matrix may be 2270
mats.
+ Trace (AB) = Trace (BA)
(Distributive taw)
Gi) Positive Integral Powers of a Matrix
‘The positive integral powers of a matrix A are defined only
‘when A isa square matrix.
Also, then A?=A:A, A? =A
Also, for any postive integers m,n
° ata sat
«ata acaye
© M=nmst
AP =z, where A is @ square matrix of order n.
aA
Example 7 1/ matric |
cose
Caan cos
oP P+! (@) None of these
on pepal! |) 9 ~ancoray
saan rel Haan |
0 -uni2))
tne) 0
Elen
or
Lf tanray
=1an(@/2)
eos sing
2U-P\ sing cose
Scanned by CamScanneree
150 | CHAPTER » Matrices and Determinants
1 tam(o/2)]fooso al
“Lranigr2y 1
ind cons
c0s9-+tan(6/2)sing ue isteril
~1an(g/2)c0s@+ sing tan(9/2)sing +eoso
1 2sin®(Q/2) +2sin5(Q22)
n(9/2){208(G/2)~1}+ 2sing/ 2809/2)
~2sin(/2}e0s(9/2) + Sea
tan 2) 2sin/2cos(g/2}1+(1~28n2(472)
jo “et ap
fang)
Hence, (bis the coneet option
2-1
2
Example 8 fa = =4A-nl =0, then n is
Jeo 8
case
3
Solution
Hence, (b) is the correct option,
]
@.
231)
Example 9 17 112]]0 4 2|} 1/0, shen she value ofx is
032
@-t wo
Solution ‘The LHS of the equation
F
H[2e 4+ 9-25-5]= dred
@2
Thos, = xed
Hence, (ais the comet option
_[co10 sino
Example 10 20 -[ mal then the value of
£(0)-£@) &
@ EO) © FON) © Fa) Ea-py
Solution £(c- EB)
sin )
cosB.
cos sin + sinceou
incsin + cosa
=sinB
[scm
-(
melo
cos —cosasinB.
a+)
= [-singce#B) costar+P),
Hence, (¢) is the correct option.
Eo sinta+B)
crm. yae[? 2) ene me
(a) 22 15 ©-10 7
seo hte os OO RENEW EA tty
cunts
7
6-4f7J-3
Hence, (b) is the correct option
ome of IEE
@ =1 @)x
@x=3,y=2 @x=2y=3
Solution The given matrix equation can be written as
xt2y)_[5
EEE)
= x4 2y=Sand 2x +y=4
= xehy=2
Hence, (b) is the correct option,
I Transpose of Matrix
If we interchange the rows and columns of a matrix A, thet
the matrix so obtained is called the transpose of A and iti
denoted by AT or At or A’,
From this definition, it is ‘obvious to note that
(@) Order of A ism xn => order of ATis n xm
© A=, Vij
Properties of Transpose of Matrix
TFA, B are matrices of suitable order, then
@ Area
i) Asay oat gar
Gi) (A~ByF = at gt
Go Gay? kar
©) (ABY = pt ar
hy ADT = AP AP At |
8 AY Lay re
Scanned by CamScannerool
mee ET
-7 28428) [1 0}
“2 748 JLo 1
Hence, (a) is the eorret option,
Example 14 17 A:
4 a
CM
aaeaote
off) off f]of] omcven
ws
a
-6 al
fs 9
i (ABY lk 4]
Hence, (0) isthe comect option,
soon Bf
I Symmetric and Skew-Symmetric Matrix
‘Symmetric matrix A square matrix A=[a,] is called
sgmmetic mati, if 4, =a, forall i,j or AT=A
sf e.
iad Sa 2S a a Syme aes)
fatimam nimber of diferent clement ia a symupetic maint is |
nit)
Skew-Symmetric matrix A square matrix A=[a,] is
called skew-symmetric matrix, if ay =—aj., for all i, j or
Nana
a Ong
eg, |-h 0 Ff
-e -f 0.
a giao Seine wi ee
mtn yg a
oe hs
ei geaaieuny whine
CHAPTER » Matrices and Determinants $ 151
Properties of Symmetric and Skew-Symmetric
Matrix
(@ IEA is a square matrix, then A+ AT, AAT, ATA are
symmetric matrices while A ~ AP is skew-symmetric
matrices.
(ii) TEA and B are two symmetric matrices, then
(8) A#B,AB + BA are aso symmetric matrices.
(b) AB ~ BA isa skew-symmetsic mauix.
(©) AB is a symmetric matrix, when AB = BA.
IFA and B are two skew-symmetric matrices, then
(@) AB, AB~ BA are skew-symmetric matrices.
(©) AB + BAisa symmetric matix.
jv) IFA is a skew-symmetric matrix and C is a column
‘matrix, then CT AC is a zero mati.
(0) Every square matrix A can unequally be expressed as
sum of a symmetric and skew-symmetric matrix £e.
-[husarfLe-a]
bere 5 4=[ 7] enema pa
ole] ol S|
1 9] 0 sit
ofa a] ol,
(ava yantcoL aa
Solution Let A=B+C, where
2
respectively symmetric and skew-symmetric par of A.
Now,
04
Hence, () is the corect option
1 Determinant of a Matrix
Ca
If A=|a, a3 a| be a square matrix, then its
determinant, denoted by IAI or det (A) is defined as.
Ca
yay
Scanned by CamScanner182.4 CHAPTER » Matrices and Determinants
Properties of Determinant of a Matrix
G) lAlexist > Ais a square matrix,
(i) LABI= ALIBI
(a LATI=1A1
AL = Al, if A is a square matsx of order
() IEA and B are square matrices of same order, then
14B! =1BA\.
(i) IFA is skew-syinmetic matrix of odd onde, then Al =0
(i) TEA = ding (44,23, then LAL
ii) IAP =1AM ne N
J Adjoint of a Matrix
If every clement of a square matrix A be replaced by its
cofactor in IAI, then the transpose of the matrix s0 obtained
is called the adjoint of A and itis denoted by, dj (A)
‘Thus, fA = aj] bea square matix and Fy be the cofactor
of ay in Al, then
aaj (4)= (FP
> (ed) y= Fy
Fa
Fa
\ 4 Fa Fam Fad [Fin Fox Fm
| WPropefties of Adjoint of Matrix
If A, B are square matrices of order n and J, is
corresponding unit matix, then
© A (Gd) A)=IA1 I, = (ad AYA
{Thus, A (adj) is avays a scalar matrix}
Pad Al= 1a!
pads) =t04
(G9) ad (aj AY 1A ft
(1) a (AP) = (05 A)?
(si) adj (AB) = adj B) (ad A)
(ity adj (A") = (adj AY", me
(oi) adj KA) = HO! (ad A), Kee
in adj
«) adj 0=0
(a Ais symmetric = adj (A) is also symmetio,
saeonal =? adj (A) is also diagonal,
iy A is diagonal
ci ic) 0 mp,
ay Ai tan
fan Aissingular => 10d) AI=O
103
‘her lad dA i eu
ample 16 A=]? 1 2 day
Bam ie E 02
os m6 2 iio
103
sotuion 14i=[2 1 1]=2
Jo 02
asad (adj A= LAE LA Co Hete,ney,
== 16
Hence, (b) isthe correct option.
135
Example 17 if A. [ 5 seer mtn
p13
“4-20 “M4 oe
| 2 *] of: 2 “|
rey 2 44 4
wo 4-2]
os in > (0 ow of tee
a 4
Mons ey py -4
Solution aj (4) [= “2 «| «|| Suen
“2 4-4] | a 4]
Hens, (3) isthe comet option,
oo
9 hen a yi eg
100
16/1 1 9
hid
© Nove of these
“QHQHwg
oj
2 o|
2
rc
98 a) mtn g
Scanned by CamScanner200) flog
2 2 ofat6|1 1 0
p22) trad,
ce (0 te cones on
=8|
inverse Matrix
' and B are two matrices such that AB BA, then
ge iverse ofA and its denoted by A! Ths,
sal @ AB=I=BA
we may note from above property (i) of adjoint
in f1AT #0, then
vi adi (A) (adj A)
Tar TAT
ea
my ial 4
pus, Aenists <> [ALO
(i By = BA"
women
(adj 4°) = (adj AY
diet ew
(i) Wl Gy slat
(0) A= diag (a42,.0,) = AM! = ding (ot 474)
(iil) A is symmetric = AW is also symmetric.
(@) Ais diagonal, [Al # 0 => “Vis also diagonal.
(0) Als scalar matsix => 4-1 is also scalar matrix.
Gi) A is triangular, [Al #0 =9 A“ is also triangular.
apie 19 tose mais of [3 ae
wf Jo 1? Jot 3] of]
Selon Lt the given matrix is A, then Al =-8
wis yf? T[23
sol Ty
eek 23
im mals a
eae, (a) is tho conect option.
‘CHAPTER » Matrices and Determinants | 153
aay [ot
Example 20. 4=[2 “1 j], ae] of ont at =A hen
aa of *]1 9
sequal to
2 2 wows
of 7] [i
us “U3 v3 -V3)
Ols 16 @ | v6
“ip jie a
ae Fan gee
eae, (6 isthe comet option.
1 Some Important Cases of Matrices
(i Orthogonal matrix A square matrix A is called
orthogonal, if AAT
idempotent matrix, if A= A
AA
iy rin mic Asem Ae
‘
involutory matrix, fA?=2 or A
Go Nite mi A sq mae Al
nilpotent matrix, if there exist a P ¢ N such that A” = 0
d
ces Ae[t S] sre
(®) Hermition. matrix A square matrix A is hermition
Scanned by CamScanner154 f CHAPTER « Walrices and Determinants
(vi) Skew-Hermition matrix A square matrix A is
skew-Hermition, fA =—A® Le, ay=— a, i,j
(vi) Period of a matrix If for any matrix A, AM! = A,
then k is called period of matrix (where k is a least positive
integer)
eg Haba
and 2+
(taints [2 2)
oe a
HPO) se isa dif tiation of matris
2,0 #9) annette
(ix) Submatrix Let A be m x mattin, then a matrix
obtained by leaving some rows or columns of both of A is
called a sub-matrix of 4.
9 Rank of a matrix. A number r is said to be the rank
of am xn matrix A, if
(@ Every square submatrix of onder (r+ 1) of more
is singular and
(B) There exists atleast one square submatrix of order
+r which is non-singular.
‘Thus, the rank of matrix is the order of the highest order
‘non-singular submatrix,
129
Example 21 The rank of matric A=|4 5 6| is
345
@2 os ws
Solution We have, IAI = 0 therefore (A is less than 3, we observe
ws
16
oa [3 9] ea msn
Hence, r(A)=2.
Hence, (a) is the correct option.
vas
esr)
‘© Element
1 Determinants seat ;
‘nan algebraic or numerical Expression is eg
sv mses meen ira
Ismet a determinant ofthat expresso, Forexangyg§
ay
expression aby ~ 6 feelaosavaa [PS © OS
Joab bate 0 joo aoe
carein @ @+e+2—3abe — (b) a*b—be
(@) AP © GP oo @ @abec
. © HP (@) None of these 2S. Ihab +642 a2
-a? ob ae G4a%)x U+8%)x (1+c%)x|
18. Uf} ab 6 be |=ka*B%c?, then & is equal to and f(3)=|(1+a)x L+b2)x (L+e*x| thenfiii
ac be -e Gta )x (4b%)x (eeyx
w-4 2 4 polynomial of degree
o4 os @ 3 © 2
©1 @o
aoa 26. The value of the determinant
19. If a +6 +e" =0 such that 0 Bee on
op
then the value of is 5 8, OTB isequal to
@ 0 (b) abe BF 9
(© -abe (@) None of these @ Obed ® a9.
ore kat fee © -2 B42
20. If] 6 (cay? BF |= kabela+b+e), then a7 fn? 888 sink
oe (a+b) i ae Teos?8 — cos@ |=, thensind is
si
the value of k is 45in481+4sin 49|
“1 wt equal to
a 2. @ in
©2 O-n 1
@ a
EEE
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piowing sem of equations 3x-2y+2=0,
a5 peisent, 427—Aen00H lon oer
nya ec fe B iseaual to
- m2
@! @s
© jereasech- and x-3y+2=0 has
777 sauion fr kis equal 10
a @) 0
6 } @2
fraayrenOden ay ~B2=0, 839420 has
ge ero soliton, then sequal to
fel wo
a @-3
41, Tenanbe ofsotion ofthe equations,
etyez 0 3 4y—
)x=3y+z=0 is
©) 1
wo
2 (@) infinite
"sins cose
sa. HF AG)=|n! sin cos], then the value of
aa @
Eicon at xe0is
@-l wo
@. (© dependent of a
33. the system of equations, x+2y—3z=1, (k +3):
(2k+I)x+z=0is inconsistent, then the value of kis
@-3 ® 12
@o @2
‘A. the system of equations, x—ky-z=0, kr-y-2=0
ad x+y-z=0 has a non-zero solution, then the
possible value of k are.
@ -1,2 & 1,2
or @-11
$8. Uf g.0.,0).4d ye ate in GP and a, >O for each i
then the value of the determinant
loge, logayas
A=) l0ga,.6 1Ogayey 1084p.40| is equal to
NoBGni2 IOBGer¢ HORA ys|
2
(@ None of these
logan,
@1
oo
36.
37,
38.
39.
40.
a.
42.
CHAPTER » Matrices and Determinants {161
‘The system of
linear equations, x+y+2=2,
Qety—z=3, 3x+2y+ke = 4 has unique solution, if
@ 20 () -leke1
© 2eke2 (@) k=0
‘The system of equations
Amy a2, Ixy 42m =-6 and
35,4, tay =-18 has,
(@) no solution
(€) infinite sotution
(b) exactly one solution
(@) None of these
inant of ax? +2br-+cis negative,
be
ath brke 0
(@) positive
(b) (ac—B (ax? +2bx+e)
(©) negative
@o
If-xis a positive integer, then
xl @#D! G+)!
(HD! (+2)! G43)!
(x+2)! +3)! +4)
@) 2eder4D! ©) Axdx+ DIG)!
© ANyir4H! (@ None of these
If the system of linear equations, x+2ay+az=0,
x43by+be=0, xtdeytez=Ohas a
solution, then a.bs¢
(@) arein AP
(©) are in HP
‘The system of equations
axtyteso-l
xtoyteza-t
xtytor=a-1
has no solution, if «is
a-| is equal to
(©) areinGP
(@) satisfy a+2b43¢=0
re 3
© -2 @) either-2 ort
tae 2) aye
«
@ -2 (b) 2
© -4 @4
it Ae|t 1] den at is equal to
of ten a ie
an
of *|
14
® ( Hl
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44.
45.
46.
47.
49.
50,
51.
52.
| CHAPTER « Matrices and Determinants
=, sand ony it
© dr2.B~0 — @) An0.020
© A200 8-0 td) Nosed ce
fr 3 ave
Yiwemavic|2 4 {ising ten 2 ineg
ps0]
y
@ (b) 4
o2 @ 4
ab
taf Jon 40, ton he num
(a) 2 3
od @ 5
ao
It alt 5 then for what value of 4,4? = 0
fa) 0 ) +1
©) @t
200
If A=/0 2 0|,then 4? is equal to
002
(b) 104
(@) 324
Which of the following is incorrect
@ AB? =(A4 By A~B)
() (ATI =A
© (AB)" = A"B", where A, B commute
(@) (A-DU+A)=0 6 A? =7
‘Matrix theory was introduced by
(b) Cayley-Hamilton
(@) Newton
(©) Cauchy @ Euclid
‘Which one of the following is not true
(2) Matrix addition is commutative
(©) Matrix addition is associative
(©) Matrix multiplication is commutative
(@) Matrix multiplication is associative
Choose the correct answer.
(2) Every identity matrix is scalar matrix
(b) Every scalar matrix isan identity matrix
(©) Every diagonal matrix is an identity matrix
(@) A square matrix whose each element is 1, is an
identity matrix
10 Lo
welt 8 are! Fs is
following holds for all n21, (by the principal of
‘mathematical induction)
(@) AT =nA+(n-DI
(© At =nd-(n-D
(0) AN=2"' At (a=
@ AN=2"4-(n-DI
34.
55.
56.
57.
58,
59.
60.
61.
62,
63.
|
ingular matrices, then,
) AB
@ (aay!
(o) (ABY = AB
43
“Adjoint ofthe max ¥=|1 0 1 (iy
443
@N (b) 2N
( -" (@) None of they
From the following find the correct relation
(a) (ABy=4'8" ©) (AB) =H
1 @) (ABy opp,
© ae 1) (ABY" = pip,
cose sing * 6
~ and A adj (A) =|
woth Be ain
is equal to
@o 1
(©) sinctcose (@ cosa
Ia matic A is such that 34° 424454405
its inverse is
(@) -GA7+2A+52) (0) 34? 42445)
(©) 34*-2A-51 (2) None of these
IFA and B are square matrices of the same order, ty
(a) (ABY = A’B’
() (ABy=284"
(©) AB=0;if |Al=Gor!Bl=0
(@ AB=O:if A=1orB
Which of the following is not true?
(@) Every skew-symmetric matrix of odd orders
non-singular
(©) If determinant of a square matrix is non-e
itis non-singular
(©) Adjoint of symmetric matrix is symmetic
(d) Adjoint of a diagonal matrix is diagonal
adj (AB) —(adj By(adj A) is equal to
@) adjA-agje oT
@o (@) None of these
t-rd 427
let A=|2 1 3) ana Gqe=|-s 0 a).t!
rug 1-2 3,
is the inverse of matrix A, then ais
62 22
@ -2
For any 2x2 Mmawix A, if =['> Oh ee
1 f ACadjA)=| 9 oh
1A1 is equal
@o
© 2 ov
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o 1 ol,
oo4
shyt poked wine sale Ry thon pl
alas (@4)
@ 610)
Ore
A
2
Pa
2
) 6-1)
@) 6-1)
vi .
a-(, i and Q=PAPT, then
peg)? is equal to
1 2005"
@lo 1
Bal
1 | @ 1
© lpn 1 0 2005
6 Aisa nit matix of order, then A(adjA) is
(a) zero matrix (b) row matrix
(@) unit matrix (@) None of these
TPA and B are square matrices of order 3 such that
, then 13AB I is equal to
@-9 (& -81
© -27 @ 81
(& Ae and BO are nxn matrix such that AB =
then
(@) det(A)=0 or det(B)=0
and det (B)=0
aet(B) #0
w [82 5]
18
72.
.
@ at=Bt
p be
6. War pbeqerand|p+a qth 2
abr
1 is equal to
74.
7S.
CHAPTER « Matrices and Determinants ) 163
on Bo
I n#3b and 1, 0,0 are the cube roots of unity, then
1 ot oF
a=|o% 1 ot | asthe value
ort
@o oo
ow @.
For postive numbers x,y and z the numerical value of
1 tog, y log, 2|
the determinant [log,x 1 log, 2| is
logex loy 1
@ 0 wd
(©) oe, 92 (@) None of these
If x=ey tbe, yaazter, r= bray (where x Yo 2 a6
not all zer0) have a solution other than x=0, ¥
2=0, then a, band ¢ are connected by the relation
(@ at 4btac? +3abe=0
(b) ab +b? +e +2abe
(oe) 4b ee + 2b
(@) 4b 422 —be-ca—ab=1
If Al denotes the value of the determinant of the square
‘matrix A of order 3, then |~2A lis equal to
(@ 1A (b) 8IAl
(© Al (8) None of these
If the system of equations, art y-+2=0, xtby+2=0
and x+ytez=0, where a,bc#1 has a non-trivial
solution, then the vale of 14 +h is
Ta be
@ - 0
©1 (@) None of these
IEA is a matrix of order 3 and | A! 8, then Jadj Al is
equal to
@ m2
©? .@%
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2
3.
4
‘Answer and Solutions
ep eet 0430) [040 42 gy.
te ey arti] bb
eal am * @ oe arse a+6b| | 2% ‘|
e [ib ofby RAR RIOB-K 8 at =
ee (Bh,
bee bk
ponding, a—byb-eN(e-a) 1 "
tex
158 6 {i tte Tre
@ acti 5 feo iga=tmasc=c) © 11 ie
1s e atx oF (E26r6+
Le a] fro 0 @ pr Aan ‘eres
@ lo of 1/-|1+0+0? of 1 ate —%
jo? 1 | [itoro? 1 o te
4 2 raft x 1 ie
0 o oF ye 14x
=|0 o 1
101
oO 1 @ Mohek
re the
a-x cb aan mF ao
@}e bx «fe = (243s? = 0 4=0,0,-3
bo a ex
rea be
aebrene "2 7 @|b xe a |=0
=> latbte-x b-x © a xtb
Jatbte-x a
os lob ©
= (rtatbtoll xte a [=
a-Laht bx
= ¢ ah 7 1 oa xb
(904646)
(by hypothesis) > #=-(atb+0)
or 1{(6-x)(c-x)-a?}~c{e-x-a) is one of the root of the equation.
+bla-b+x)=0 b b-c ¢
by expanding the detrniant 8. ©) A=@-a)b-a)Ja a-b b
or PCa? +6? +62) +(ab+be tea) = cca a
or #-(Se!)-HS a) =0 an;
=(a~e)'/a a lq q)
0 by Gt
{rattec=0=carseo?=0 cee
Va a be
2 Le sE eba0s Yara} % @ |Ub Bog
Ve
or x28 25a! °
‘ 1 @ abe lat
2. The solution is x=0 or ‘abe|! 2 abc] = abe] , #20
1? abe)
abe] Vet
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ety yz sty y 2
(by RAR +R+R)
raid
s(xtyt2)|x 2% (by G 9G -G)
yz
a lety tod -9)- Ge) 49-9}
a (rtyta(z-9? > kel
37 rid
12 @ [2 x 2J-0- 49/2 * 2| i
7 6 2 76%
(by RR +R +R)
=> (14 9){(a2-1)-@x-14) 402-720)
> (e+ 9) (a? 9x4 14) =0
> (xt 9MR-DUE-D) =
Hence, the other two roots are x= 2.7-
13, (a) Splitting the determinant into two determinants, We
lag lad
ged b o|+abclt & 2°?
1c A re
= atabesiiaDyb-O1(e- =O
Because a, b ¢ ate different, he Sh 0
cannot be zero, Hence, option (2) Labe=0, is
‘comrect.
14, (b) Since, itis an identity in 2 so satisfied by every
‘CHAPTER » Matrices and Determinants 1 165
value of %
Now, put 2=0 in the given equation, we have
0-413
te|1 2 ~4]=-12430=18
340
1a bee
b cto
1c asp |
11 bee|
=(a+b+o)f1 1 etal (9G+G)
11 aso i
=0 ase)
16. (4) Muliplying by a/R, by and R, by , we have
, me we aba
Lathe? abe be+ab
‘abe |"
abc abe actbe
be 1 ab+ac|
jac 1 be+ab]
Jab 1 ac+be!
be 1 Zab
fac 1 Zab]
jab 1 Eab|
be 11
= abe-Eablea 1 1
jab 1
ab aatd|
be bate|
jaa+b bate 0
abc
(by G9G+G)
=abe|
2G)
@ ae
ab aatd
[bc bate ‘
0. 0 ~(aa? +2ba+e)
by RIK-AR-K)
faa? + ate)~0}
bac +2ba.+€)~9}
(by expanding along G.)
al
=P -acy(ao? +2040
‘thus, £0, either B? -ae=0
aot +2hate=0
or
fe, ab and c inGPor ant #25046 =0
Scanned by CamScanner1185 7 CHAPTER » Matrices and Determinants
no ab ae ©
18. @ fad 8 te .
ae be -< ~
!
att
=tebeyabe] tt 1]eae'eenes
to
sabe = tac? (given) => kad
1p
11 tel
Applying CC, =, and C9 0, —
lea dod
19.
|
1 bo
1 06
Onexpanding wert. R
ab+bet cat abe =, “
4b et e9
ie
Given,
= Aetstao = abeterca=o
= debe {from Ea. ()}
20. (6) Operate C; +6, -G.C,-»—C, and take out
2+b+¢ from C, as wells from C to get
+e) an-b-e a~bae|
A=@tb+e)' | B ctay 0
0 atb-e|
(Cperate & + R~ RR)
he 20th
= (atb+e)| Be cta-b oO
0 atb~e
Crete 6-566, a 6464469
be 0 0
= latb+cP| erg &
Sand
=(a+b +c} 2bel(a+b)(e+a)—be))
=2abe(a+b-+e)
21. (b) Given, angles ofa triangle = A, Band C,
We know that as A +B + C=", therefore
A+B=n-¢
oF c0s(A+8) =cos(n—C).
or cos Acos B—sin Asin B.
c0sC
0s
vy
08 ACOs + 208 =n Aa
sin(A+B)=sinGe—C) = sing
and
expanding the given determinant, we gy 5
ge ntl- cba?
-o a ¢
ab aw?
=0'o|-) © bo?
~c a ca?
ab al aba
=@l-b c ble -w'[5 ¢ ple
-c a | cae
25. 0) Applying c, PG+G46,
1 +6 yx
FOS py a2y
1 46%)
A+e*)x|
(+e*)x|
I+e7x ‘
(rat eee +cte2e0)
Applying RR, — Rw» RA
1 +b) d+ery
=)0 ans 0
Dens 20,
eM, deste off) 9
= (xP
Inx
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0,
a
1. (©) Ithas a non-zero solution, if
pp
sped 0
ott
-aja’—b 1 t}=0
ab 1
ae
wae
(624-4 898. FG =G) andthe aking
sor common (O'=a") from 2rd column and
(ee?) om 3ndeolama}
sin'@ sin?
Lreos?0 cost
4singd 1+4sindo
1+sin"@
cos?
sin’
(using CG, 96,-C,,6, 9G-G)
1 0 sinto
-1 1 cost@ |=0
0-1 1+4sin4o|
2
(© Thesystem of equations has infinitely many
(non tivial solution, if A=0 i
3
a -14 15]=0
123
342-30) 046-2) +1(-30+14) =0
aes
2(1+2sin 46) = 0=> sin 48:
2
>
>
1k -
3 -k
13]
> 6k +6=0=k=1
(@) The given system of homogeneous equations has a
nonzero solution, if A=0.
1 4-1
ie, [3 -a -3|=20-6=0 ie, if a=-3
131
(©) The given system of homogeneous equations has
144i
as)3 4 -
13]
=7-16+540
‘There exists only one trivial solution.
(4-3) -4G+1)- 1-944)
32,
CHAPTER » Matices and Determinants | 187
)
= [One .
nt sin(o4 2)
33.
(2) For the equation to be inconsistent
123
0 0 k43
+101
123
300
ood
‘So, that system is inconsistent for
For non-trivial solution
1k
k -1 -l}-0 =
ae
Ifris the common ratio, then
a, = ar" forall n21
=05k=-3
and D,= #0
34.
@
>
35. ©)
= loga, = loga, +(n—Dlogr
=AHH-DR,
where log, = A and logr=R
‘Thus, in A, on applying GCG and
6, 9C,-C,,we obtain C, and Cyare identical
‘Thos, =0
36. (a) The given system of equations has a unique
rid
solution, if|2 1 -I]#0= #0.
32k
Scanned by CamScanner166 1 CHAPTER » Matrices and Determinants
bent
p-[s -1 2
we oft
[-1-2}-16-3}4+13+3]=0
2-11
and Baf-6 1D
sd
38,
39,
(1=2)-1(-36+6)+ 16-18)
=-6430-
Aso, Dy =0:D,=0
So, the system is consistent
(D=D, =D, =D, =0)
de system has infinite soation.
a b axtb)
be, Bete
Jactb bene 0
Applying —> Ry—2R,—Ry, we get
|
© Lea-|
ab arte
A=|bc brte
100 ~(ax* + 2br+0})
A= (6? ac) (ax +2bx +e)
Now, #?-ae<0 and @>0
= Discriminant of ax? +-2bx+c is ve and a>0
> (@P +2br+e)>0 forall xeR
3 A=@-acy(ar* +2e+0)<0
© A=leryr (e421 C43)
Ke+2)1 G43 ebay
1 Gt) @+2@4n
rakes (42) (x43 (x42)
1 (+3) (r+4y(x43)
Applying &, > R,~R,, Ra (RyRy), we get
Ot ara)
“Hermes 1 mn
1 43) rtaerssy
(on simplification)
the altemate,
1 GD! a
= 221+)! (242)1
‘Trick Put x= 1 and then match
(Ry RRR
o a
b bea
2e-b c-b
(b-ay2e~b)=0
tony
0
a,b care in HP.
41. (©) For no solution or infinitely many solutions
ail
1 @ 1/=00=1a=-2
Lia
But for a=1, clearly there are infinitely may
solutions and when we put = ~2 in given syne
of equations and adding them together,
LHS # RHS ie., No solution.
42, (@) M?-2M-1,=0
ray. 2] pa 2a) 71 oy
cael As 3ay"[o a>
> falls SH, the
= 5-2 8-20] [1 4
8-24 13-32] lo 1]
= S-2=1,8-20=0,13-3021
= 2=4, which satisfies all the three equations
soe TL
af OP Lf
44. @ Since, AB=0, sevenif A* Oand B20.
13 As?
48.) Themauix|2 4 8 |i
35 10
13 Ase
24 8
gular, if
2042) 125,24
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;
aoa? ab ab?)
Wedd? eOand A* =O. forall n22,
a Te ‘]
o peene -all-1
(as given)
1g. (0) Since, (A+BXA~B)
By matrix distribution law,
= A -AB+BA-B = A? BP
> BA-AB=0=> BA= AB
50. (b) Students should remember it.
51, (©) tis property of matrix multiplication,
52. (a) We know that every identity matrix is a scalar
matrix.
awed eb]
AEH
ractecore[) fea
nd
54 (@) Weknow tha, if and B are non-singular matrices
ofthe same orders, then (AB)"' = BA,
4 3-8
5. @ Teeofacorsof N=] 1 0 1 | are
56.
57.
(CHAPTER « Matrices and Determinants } 169
43
se agy=] 10 1 i=n
443
(b) tis obvious.
ote a(S me
-sina cosa
ha cea
[fre ae
2 alta}e Te wap of mati of ct
cosa sing!
singe , cose
cosa sina]feosa ~sina’
ina cosa.||sina cosa.
[eae a]
(as given)
> kel
(@ 342424? +5A+1=0=9 1 =-34?-24" ~5A
= 34-24-51
> GA? +2445)
() (ABy’= BA, by definition.
(@) Every skew-symmetric matrix of odd order is
singular. So, option (a) is incorrect.
(©) (ABy! = BtAT
aadj(AB) _ adj(B)_adj()
1ABl~1BI LAL
= adi(AB)—adj(B)-adj(A)=0
422
(@) Given, |-5 0 «|=1047
123,
42 a - 10 0 0)
=J-5 0 aff2 1 0 0 0
raga 0 0 0)
(Equating the clement of 2nd row and Ist column)
> Stas0>a=5
(b) Weave, aesiay=[") al
0 10
10 ;
oe a0aiey=10h, t]eo" ~
and ck catia)
vai
Aadja)=1AUL
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170 1 CHAPTER « Matrices and Determinants
++ From Eqs. ) and (i), we get
1 0 of fo 9 °)
106
valde as
24) lo 10 v4
Jao 0
lo oa
S6=lterd
* (6,11) satisty the relation
65. @) If = papr
PTQ™*P = apt gt p
=#P"O™p — geprgimp
=A™ PT Op)
=4a™pr (ps)
(Q= PAP" = OP = pay = 4mms
ams _[1 2008
> of a
66. (2) IFA isa singular maui of order n, then
A(OiA)= (adj A)A = 0 = 2er0 ment
67. (a) Weknow tat, if 4, Bare n square matics, then
1ABI=1A1IBi
68. (@) 420 nd B20
* AB=0
Hence, det (A)=0 or det (B)=0
Pob e¢
69. ©) d=|p+a 945 2cln9
ob
Applying Ry —> RR,
Pbe
=]a ¢ cso
ao,
Applying Ry > R—R and >, —@
Po ob ¢
a-p q-b 0 [a
Ja=p 0 re
(by equality of matrices)
(as PPT =1)
wv
Pag
(On expansion, we get
p(q-bXr~C)—B(a~ pXr~e)
(4 -bXa~
= (p-aNlg~0Xr-0)
pi, b
[ea (q-) es
= (p~anq-BNr-0)
A
a
peagebrec
70. (a) Applying GC; +C,+C,, we gt
1+@" +0" "a
A=|1+o"+o0" 1 gt
Ow" 1
140°+0" =0, ifn is not muliple ot)
1 tos.y tox, 2
71.) fiog,x 1 tog, z
Joa.e lony 1
© (les, log, 2)—log,y(log, x—Iop, i,
++log, (log, xlog, yi
= (-D-A-Iog, ylog, 2)+ (log, zlog, x~1
Colog, y-log, 22!
72. (©) The system of homogeneous equations
tebe =0
ot ytar=0
betay—
Ee ks
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©
it solution 1 isa 1=b" ie
1
erp 75. @ Wetwon, aaiiaele ial 0
. 0 0 SAL
alice ot ole (B28 WAL 00
oem Oo 0 IAN
a ab Ne-D-Md-ae-n
-1l-a)(b-1)=0 : JAl-adjlAl= VAP
> P or adjlAl= 8 = (2 = 2
a
Scanned by CamScanner1 Relation —
ita Sty aid
‘ ‘Thus, if Ris a relation fro A to B, then R B.
Tf an element a € A is associated with b € B under the
function f then the element bis called the J image of « or the
value of f at a It is denoted by the symbols
bas a) or fra bor (a bef
‘Also, ais called the pre-image of b under f.
Example 1. f.Z +2 f(a) =3r— 4 is a faction, while
MeN Nf) = ax ~ 4 is no a faneton Because image of
1 e N under f does not exist in N.
Scanned by CamScanner174-1 CHAPTER = Relations and Functions
le oN, F(a)= VF is not a function because
ce pena ets Sata
Reicks y
Whether (14> Bis fneton or not tet the flowing
4 Bnistence of fimage of very clement of di the st.
2 Uniuencs of fmage of every lament ofthese
1 Function as a Set of Ordered Pairs
‘Afunctonf: A > Bean be expressed as a st of ordered
air in which frst element is the member of A and second
Element isthe member of B. Hence, fis «st of ordexed pais
(a. 8) such that
(ais an clement of A
G@bis an element of B
Gdn two ordered pies off have the same frst element
Gv)every member ofA is first element of one of the
ordre pais off.
4:A~ Bisa subse of Ax B, His expressed inthe form
of ordered pits a follows
17 ((@ b=F0),0€ Amd be B)
Example 3. A=(0,1,2),thenf= (0.3). (49,0) na
fection from Ato H bat = (0, 4 (2, )} and b= (0,
(0,4) (1,5) 13) i ot a finton fom AN.
Example 4: N+ N, fie) = 2x-+ 1, them the terms of
ordered prs $= {0,3 23), 7), od
1 Domain, Codomain arid Range of a Function
Suppose that fs a function from A to B, ie, f:A > B,
then set A is called the domain and set B is called the
codoman, 1
Also, the set ofall images of the elements of A is called
the range of f and itis denoted by f(A),
Therefore (A) = (fa)! a A) CB. I fis expressed in
ferms of ordered pairs, then set of first element of ordered
Pairs off willbe domain and set of second elements of these
ordered pairs will be range off, ie,
Domain of f= (r1(3,9)< f)
Range of f= (y 1G, ef)
The Set Ys also called the codomain off, clea,
SOsY.
x
nae given figure find the domain, cody,
a
:
ee
ba
:
+ Domain of f ={P. qr. 5)
4 codomain of f = Cl 2,3, 4,5)
Range of f = (1, 2, 3)
ae
domain, codomain and range of function.
Domain of f=
Solution
Codomain of f= W and Range = (3,5,_)
Example 7 ff: Z>Zf@) =k then
‘Sokaion Domain of f= codomain of f= Z and
Range of f= (0, 1. 2,3, 0)
I Identity Function
‘The function f: R — R is called an identity function
f() =x, Vx R. The domain of this ‘identity function ist
and its range is also R,
1 Equal Function
‘Two function fand g are said to be equal funtion,
only it
© domain of = domain of
(i codomain of f= cod
lomain of
@ Fe) 2
= 802. V x6 their common domain
162), B= (10,13), f:4-+B,
BAB, acy
Example 8 74
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y
65 te id he dana of ston
1
aay
javier F73
geneninet=(5")
je 10 Finds dont of hereto 0) = VTE
wl
e pex2d lee
won
ponle
reco l
Find the domain ofthe function
vo
Fara given function to be defined
w(t jee 2!
se-P26 22-5465
5 G@-De-DS0 exe)
ample 12. Find domain of (3) = logy +2°)
adn (6) =logy( +29) exists, if 14.2> 0
(9+) > 0, where (= +29 fs always
putin ss D 0
site
21
xe} het
‘Tins, domain of above function f(x) is (-1, =).
Number of Functions (or Mapping) from
oY
Vet {3% oo Aq) (Kee elements)
tod
ip 3o Syren Jy) (Les, m elements)
Ther, each element in domain x; (¢ = 1, 2, 3,
comesponds m images
fixoy
x m2
t
Thus total number of function from X to ¥
é = nxnx.m times =n"
+ (Number of elements in in Master emesin doin
CHAPTER « Relations and Functions { 175
1 Representation and Testing for a function
@) Mapping It show the graphical aspect of the relation
‘of the elements of X withthe elements of ¥.
@ fixoy
x
©) fixry
\_
pL ——\
© h:xXo¥
x
In the above given mapping rule f, and f, shows a
function because each element of X is associated with
‘unique element of ¥. Whereas f, is not a funetion because in
{fa clement ¢ is associated with two elements of Y.
Algebraic method tshow the relation between the
‘elements of two sets in the ftom of two variables x and y
where x is independent variable and y is dependent variable.
If X and ¥ be two given sets. X= (1, 2,3), ¥= 15.7.9)
then f:X9 Yy=fla)=2+3
(Gi) In the form of ordered pairs A function f:X— ¥ can
be expressed as a set of ordered! pars in which first element of
every ordered pair is a member of X and second element is the
member of ¥. So, fis a set of order pairs (a, b) such that
@) ais an clement of X
(©) disan element of ¥
(©) Two ordered pairs should not have the same first
clement.
(iv) Vertical line test for a function If we are given a graph
‘of the relation. Then, we can check whether the given relation
is. function or not, IFitis possible to draw a vertical line which
‘cuts the given curve at more than one point, then given relation
is not a function and when this vertical ine means line parallel
to y-axis cuts the cucve at only one point, then itis function.
Figure represents a function,
Scanned by CamScanner176 1 CHAPTER « Relations and Functions
%
| Classification of Function
@ Constant function Ifthe range of a function f consists
‘of only one number, then fis called a constant function.
0.6)
reac
egaLet fc) =:
@ Identity function The function defined by f(x)
Wax R, is called the identity function,
Where ¢ is a constant number.
a
6 x
2 Modulus function The function defined by
F@)=1x
is called a modulus
>) Signum function The function defined by
8h aon rao [when «
rol nese ere
9. when 200) EE 22
is called signum function,
(©) Greatest integer function This function ig
fx), where [2] = greatest integer less than oF equa nh,
y —
«Ld
Important Identities
+ fds. (Ohisis always true)
+ Gitex
Properties of Greatest Integer Function
@ [x)=x, holds, if x is an integer.
@) [e+ 1]= 13] + £ if Fis an integer.
© b431=b+Dhif be} 4+ 6) <1
=] +D1+ Lif (2) + (y} 21
© WE EA then 27
TE (21S 4 then Ga) < 47
~ ff xe integer
[el-1,ifx @ integer
() Fraction part function (x) denotes fractional pate
Its equal to x~ [x].
*& 27}207,
£32)a0y° 8)"
n= R
Range =(0, 1)
(A Teigonomet
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