Maths Practice Set - 17
Maths Practice Set - 17
1. There are 100 students in a class. In an 9.If 𝛼 and 𝛽 are imaginary cube roots of unity,
examination, 50 of them failed in Mathematics, 1
then 𝛼 4 + 𝛽 4 + 𝛼𝛽 =
45 failed in Physics, 40 failed in Biology and 32
failed in exactly two of three subjects. Only one (a) 3 (b) 0
student passed in all the subjects. Then the (c) 1 (d) 2
number of students failing in all the three subjects 10.If 𝜔 is a complex cube root of unity, then
a. is 12 b. is 4 (1 − 𝜔)(1 − 𝜔2 ) (1 − 𝜔4 )(1 − 𝜔8 ) =
c. is 2 (a) 0 (b) 1
d. cannot determined from the given information (c) -1 (d) 9
2.If 𝑛(𝐴) = 8 and 𝑛(𝐴 ∩ 𝐵) = 2 then 𝑛((𝐴 ∩ 𝐵)′ ∩ 11.If 𝜔 is a cube root of unity, then the value of
𝐴) is equal to (1 − 𝜔 + 𝜔2 )5 + (1 + 𝜔 − 𝜔2 )5 =
a. 2 b. 4 (a) 16 (b) 32
c. 6 d. 8 (c) 48 (d) -32
3.25 people for programme A, 50 people for 12.If 𝑥 = 𝑎, 𝑦 = 𝑏𝜔, 𝑧 = 𝑐𝜔2 , where 𝜔 is a
𝑥 𝑦 𝑧
programme B, 10 people for both. So number of complex cube root of unity, then + + =
𝑎 𝑏 𝑐
employee employed for only A is (a) 3 (b) 1
a. 15 b. 20 (c) 0 (d) None of these
c. 35 d. 40
4.𝐴 and 𝐵 are subsets of universal set 𝑈 such that
𝑛(𝑈) = 800, n(A) = 300, n(B) = 400&n(A ∩ B) = 13. If the roots of the equation 𝑥 2 − 8𝑥 +
100. The number of elements in the set 𝐴𝑐 ∩ 𝐵𝑐 is (𝑎2 − 6𝑎) = 0 are real, then
a. 100 b. 200 (a) −2 < 𝑎 < 8 (b) 2 < 𝑎 < 8
c. 300 d. 400 (c) −2 ≤ 𝑎 ≤ 8 (d) 2 ≤ 𝑎 ≤ 8
5. A relation 𝑅 is defined on the set 𝑅 of all real
numbers such that for non-zero 𝑥, 𝑦 ∈ 𝑅, 𝑥𝑅𝑦 ⇒
14.The roots of the equation 𝑥 2 + 2√3𝑥 + 3 =
|𝑥 − 𝑦| < 1 then this relation is 0 are
a. Reflexive, symmetric but not transitive (a) Real and unequal
b. Reflexive, transitive but not symmetric (b) Rational and equal
c. Symmetric, transitive but not reflexive (c) Irrational and equal
d. An equivalence relation (d) Irrational and unequal
6. aRb ⇔ |a| ≤ b. Then R is
15.Roots of 𝑎𝑥 2 + 𝑏 = 0 are real and distinct if
a. reflexive b. symmetric
(a) 𝑎𝑏 > 0 (b) 𝑎𝑏 < 0
c. transitive d. equivalence
(c) 𝑎, 𝑏 > 0 (d) 𝑎, 𝑏 < 0
16.Roots of the equations 2𝑥 2 − 5𝑥 + 1 =
7. A relation defined on two natural numbers 𝑎
and 𝑏 is given by a Rb : a is divisible by b . The the 0, 𝑥 2 + 5𝑥 + 2 = 0 are
condition which holds true is (a) Reciprocal and of same sign
a. symmetric and transitive relation (b) Reciprocal and of opposite sign
b. reflexive, but not transitive relation (c) Equal in product
c. transitive but not symmetric relation (d) None of these
d. symmetric, reflexive and transitive relation 17. If 𝑎, 𝑏, 𝑐 ∈ 𝑄, then roots of the equation
8.Square of either of the two imaginary cube roots (𝑏 + 𝑐 − 2𝑎)𝑥 2 + (𝑐 + 𝑎 − 2𝑏)𝑥 + (𝑎 + 𝑏 −
of unity will be 2𝑐) = 0 are
(a) Real root of unity (a) Rational (b) Non-real
(b) Other imaginary cube root of unity (c) Irrational (d) Equal
(c) Sum of two imaginary roots of unity 18. In the expansion of (1 + 𝑥)3 , the sum of
(d) None of these the coefficient of the terms is
(a) 80 (b) 16
60.The value of 𝜆 and 𝜇 for which the 69.A value of 𝜃 satisfying sin 5𝜃 − sin 3𝜃 +
simultaneous equation 𝑥 + 𝑦 + 𝑧 = 6, 𝑥 + 2𝑦 + sin 𝜃 = 0 such that 0 < 𝜃 < 𝜋/2 is
3𝑧 = 10 and 𝑥 + 2𝑦 + 2𝑧 = 𝜇 have a unique a. 𝜋/12 b. 𝜋/6
solution are c. 𝜋/4 d. 𝜋/2
a. 𝜆 = 3 only
70.The equation 𝑘sin 𝑥 + cos 2𝑥 = 2𝑘 − 7 has a
b. 𝜇 = 3 only
solution, if
c. 𝜆 = 3 and 𝜇 = 3
a. k > 6 b. 2 ≤ k ≤ 6
d. 𝜆 ≠ 3 and 𝜇 can take any value
c. k < 2 d. −6 ≤ k ≤ −2 (e)
0 3 0 4a
61.If A = [ ] and kA = [ ] then value of 2𝑥
71.If 𝑓(𝑥) = 2tan−1 𝑥 + sin−1 (1+𝑥2 ) , 𝑥 > 1, then
4 5 3 b 60
k, a and b are respectively 𝑓(5) is equal to
a. 12,19,16 b. 9,12,16 a. 𝜋/2 b. 𝜋
c. 12,9,16 d. 16,9,12 −1 65
c. 4tan (5) d. tan−1 (156)
62.For two 3 × 3 matrices A and B , let A + B =
2 B ′ and 3 A + 2 B = I3 , where B ′ is the transpose 2
72.Value of cos (3sin−1 (5)) is
of B and I3 is 3 × 3 identity matrix. Then 17 31
a. 10 A + 5 B = 3I3 b. 5 A + 10 B = 2I3 a. 25 b. − 125
c. 3 A + 6 B = 2I3 d. B + 2 A = I3 9√21 9√21
c. − 125
d. 125
63.Let f: (−1,1) → R be such that f(cos 4𝜃) =
2 𝜋 𝜋 𝜋 73.The value of tan2 (sec −1 2) + cot 2 (cosec −1 3) is
for 𝜃 ∈ (0, ) ∪ ( , ). Then the values of
2
2−sec 𝜃 4 4 2 a. 13 b. 15
1
f (3) is (are) c. 11 d. None of these
1 1 3
a. 1 − √2
3
b. 1 + √2
3 74.In a triangle ABC, a+c + b+c = a+b+c then ∠ABC
in degrees equals
2 2
c. 1 − √3 d. 1 + √3 a. 60∘ b. 30∘
c. 45∘ d. 90∘
64.If 𝜃 lies in the second quadrant and 3tan 𝜃 + 75.The angle of elevation of the top of a tower at
4 = 0, then the value of sin 𝜃 + cos 𝜃 is equal to point on the ground is 30∘ . If on walking 20
1 2
a. 5 b. 5 metres toward the tower, the angle of elevation
3
c. 5 d. 5
4 become 60∘ , then the height of the tower is
10
(a) 10 metre (b) metre
1 √3
65.If sin 𝑥cos 𝑦 = 4 and 3tan 𝑥 = 4 tany, then (c) 10√3 metre (d) None of these
sin (𝑥 − 𝑦) equals to
1 1
a. 16 b. 8
3 3 76. If position vectors of four points 𝐴, 𝐵, 𝐶 and 𝐷
c. 16 d. 4 ˆ , 2𝐢ˆ + 3𝐣ˆ, 3𝐢ˆ + 5𝐣ˆ − 2𝐤
ˆ and 𝐤
ˆ − 𝐣ˆ
are𝐢ˆ + 𝐣ˆ + 𝐤
𝜋 𝜋 respectively, then 𝐀𝐁 and 𝐂𝐃 are related as
66.The value of cot ( 4 − 𝜃) ⋅ cot ( 4 + 𝜃) is
(a) perpendicular
a. -1 b. 0 (b) parallel
c. 1 d. 2 (c) independent
sin 70∘ +cos 40∘ (d) None of these
67. cos 70∘ +sin 40∘ =
1 77. If (3𝐚 − 𝐛) × (𝐚 + 3𝐛) = 𝑘𝐚 × 𝐛, then what is
a. 1 b. the value of 𝑘 ?
√3
1 (a) 10 (b) 5
c. √3 d. 2
(c) 8 (d) -8
68.The value of √2(cos 15∘ − sin 15∘ ) is equal to
a. √3 b. √2 78. Point 𝐴 is 𝑎 + 2𝑏, 𝑃 is 𝑎 and 𝑃 divides 𝐴𝐵 in
c. 1 d. 2 the ratio 2:3. The position vector of 𝐵 is
80. If 𝐚 is a non-zero vector of modulus 𝑎 and 𝜆 is 89. The diagonals of a quadrilateral 𝐴𝐵𝐶𝐷 are
a non-zero scalar and 𝜆, 𝐚 is a unit vector, then along the lines 𝑥 + 3𝑦 = 4 and 6𝑥 − 2𝑦 = 7. Then,
(a) 𝜆 = ±1 (b) a = |𝜆| 𝐴𝐵𝐶𝐷 must be a
1 1
(c) 𝐚 = |𝜆| (d) a = 𝜆 (a) rectangle (b) parallelogram
(c) cyclic quadrilateral (d) rhombus
81. The ratio in which the line joining (2,4,5), (
90. The equation of straight line passing through
3,5, −4 ) is divided by the 𝑌𝑍-plane is
the point of intersection of the straight line 3𝑥 −
(a) 2: 3 (b) 3: 2
𝑦 + 2 = 0 and 5𝑥 − 2𝑦 + 7 = 0 and having infinite
(c) −2: 3 (d) 4: −3
slope is
82. A straight line which makes an angle of 60∘ (a) 𝑥 = 2 (b) 𝑥 + 𝑦 = 3
with each of 𝑌 and 𝑍-axes, is inclined with 𝑋-axis (c) 𝑥 = 3 (d) 𝑥 = 4
at an angle
Directions (Q. Nos. 91-92) In a circle of radius ' 𝑟
(a) 45∘ (b) 30∘
', a right circular cone is drawn.
(c) 75∘ (d) 60∘
91. What will be the maximum height of cone
83. The foot of the perpendicular from (0,2,3) to having maximum valume?
𝑥+3 𝑦−1 𝑧+4
the line = = is 4𝑟
(a) 3
3𝑟
(b) 4
5 2 3
(a) (−2,3,4) (b) (2, −1,3) √3 2
(c) (2,3, −1) (d) (3,2, −1) (c) 𝑟 (d) 𝑟
3 3
(c) 𝑐 + 𝑘 (d) 𝑐 − 𝑘 𝜋
maximum value at 𝑥 = 3 , what is the value of 𝑘 ?
96. If 𝑓(𝑥) = 3𝑥 2 + 6𝑥 − 9, then (a) 3 (b) 1/3
(a) 𝑓(𝑥) is increasing in (−1,3) (c) 2 (d) 1/2
(b) 𝑓(𝑥) is decreasing in (3, ∞)
(c) 𝑓(𝑥) is increasing in (−∞, −1) Directions (Q. Nos. 105-107)
(d) 𝑓(𝑥) is decreasing in (−∞, −1) If ∫ 𝑥 2 𝑒 −2𝑥 𝑑𝑥 = 𝑒 −2𝑥 (𝑎𝑥 2 + 𝑏𝑥 + 𝑐) + 𝐷
𝛼𝑥
119.Let 𝑓(𝑥) = 𝑥+1 , 𝑥 ≠ −1. Then, for what value
of 𝛼 is 𝑓[𝑓(𝑥)] = 𝑥 ?
(a) √2 (b) −√2
(c) 1 (d) -1