Trig WS
Trig WS
π
(b) Hence find the value of cot in the form a + b 2 , where a, b .
8
(3)
(Total 5 marks)
2. The diagram shows a tangent, (TP), to the circle with centre O and radius r. The size of
PÔA is θ radians.
(c) Using your results from part (a) and part (b), show that sin θ < θ < tan θ.
(2)
(Total 5 marks)
4. The radius of the circle with centre C is 7 cm and the radius of the circle with centre D is 5 cm.
If the length of the chord [AB] is 9 cm, find the area of the shaded region enclosed by the two
arcs AB.
Find the area of the shaded segment of the circle contained between the arc PQ and
the chord [PQ].
(Total 5 marks)
6. The vertices of an equilateral triangle, with perimeter P and area A, lie on a circle with radius r.
P k
Find an expression for in the form , where k +.
A r
(Total 6 marks)
1
7. (a) Given that α > 1, use the substitution u = to show that
x
1 1 1
1 1 x 2
dx 1 u
1 2
du .
(5)
1 π
(b) Hence show that arctan α + arctan .
2
(2)
(Total 7 marks)
sin 2nx
cos x + cos 3x + cos 5x + ... + cos((2n – 1)x) = ,
2 sin x
for all n +
, sin x ≠ 0.
(12)
1
(c) Solve the equation cos x + cos 3x = , 0 < x < π.
2
(6)
(Total 20 marks)
π π
9. If x satisfies the equation sin x 2 sin x sin , show that 11 tan x = a + b 3 ,
3 3
where a, b +
.
(Total 6 marks)
π
10. Throughout this question x satisfies 0 ≤ x < .
2
dy
(a) Solve the differential equation sec2 x y 2 , where y = 1 when x = 0.
dx
π
π π 1
(ii) Deduce that
4
0
4 sec xdx ln 2 .
4 2
(8)
(Total 15 marks)
13. Consider the triangle ABC where BÂC = 70°, AB = 8 cm and AC = 7 cm. The point D on the
BD
side BC is such that = 2.
DC
Determine the length of AD.
(Total 6 marks)
14. The interior of a circle of radius 2 cm is divided into an infinite number of sectors.
The areas of these sectors form a geometric sequence with common ratio k. The angle of the
first sector is θ radians.
π
15. Consider the function f : x → arccos x .
4
(b) Determine an expression for the inverse function, f–1, and write down its domain.
(4)
(Total 8 marks)
16. Let α be the angle between the unit vectors a and b, where 0 ≤ α ≤ π.
(b) Hence determine the value of cos α for which │a + b│ = 3│a – b│.
(2)
(Total 5 marks)
17. (a) A particle P moves in a straight line with displacement relative to origin given by
(b) Hence, find the two possible values of AC, giving your answers correct to two decimal
places.
(4)
(Total 6 marks)
π
The point A ,2 lies on the curve and B(a, b) is the maximum point.
6
1 1 π
20. (a) Show that arctan arctan .
2 3 4
(2)
(b) Hence, or otherwise, find the value of arctan (2) + arctan (3).
(3)
(Total 5 marks)
Consider the shaded regions with areas A and B. Given that A : B = 2 : 1, find the exact value of
the ratio R : r.
(Total 5 marks)
22. A triangle has sides of length (n2 + n + 1), (2n + 1) and (n2 – 1) where n > 1.
(a) Explain why the side (n2 + n + 1) must be the longest side of the triangle.
(3)
x 10
(b) Show that cos θ = .
50
(2)
(i) α;
(ii) β.
(4)
(i) Find an expression, b(x), for the length of the perimeter in terms of x.
5π
24. Consider the graphs y = e–x and y = e–x sin 4x, for 0 ≤ x ≤ .
4
5π
(a) On the same set of axes draw, on graph paper, the graphs, for 0 ≤ x ≤ .
4
π
Use a scale of 1 cm to on your x-axis and 5 cm to 1 unit on your y-axis.
8
(3)
nπ
(b) Show that the x-intercepts of the graph y = e–x sin 4x are , n = 0, 1, 2, 3, 4, 5.
4
(3)
(c) Find the x-coordinates of the points at which the graph of y = e–x sin 4x meets the graph
of y = e–x. Give your answers in terms of π.
(3)
(d) (i) Show that when the graph of y = e–x sin 4x meets the graph of y = e–x, their
gradients are equal.
(ii) Hence explain why these three meeting points are not local maxima of the
graph y = e–x sin 4x.
(6)
(ii) Show that y1, y2 and y3 form a geometric sequence and determine the common ratio
r.
(7)
(Total 22 marks)
25. The diagram below shows two concentric circles with centre O and radii 2 cm and 4 cm.
π
The points P and Q lie on the larger circle and PÔQ = x, where 0 < x < .
2
(a) Show that the area of the shaded region is 8 sin x – 2x.
(3)
x
The equation that represents this boundary is y = 16 sec – 32 where x and y are both
36
measured in cm.
The top of the channel is level with the ground and has a width of 24 cm. The maximum depth
of the channel is 16 cm.
Find the width of the water surface in the channel when the water depth is 10 cm. Give your
answer in the form a arccos b where a, b .
(Total 6 marks)
(b) Hence, by using Pythagoras’ Theorem in the triangle BCD, prove the cosine rule for the
triangle ABC.
(4)
1 3
(c) If AB̂C = 60, use the cosine rule to show that c = a b2 a 2 .
2 4
(7)
(Total 12 marks)
The above three dimensional diagram shows the points P and Q which are respectively west and
south-west of the base R of a vertical flagpole RS on horizontal ground. The angles of elevation
of the top S of the flagpole from P and Q are respectively 35 and 40, and PQ = 20 m.
33. The depth, h (t) metres, of water at the entrance to a harbour at t hours after midnight on a
particular day is given by
t
h (t) = 8 + 4 sin , 0 t 24.
6
(a) Find the maximum depth and the minimum depth of the water.
(3)
Find AC.
(Total 7 marks)
(d) Hence or otherwise, find the coordinates of the local maximum and local minimum points
π
on the graph of y = tan 2x + cot 2x, 0 ≤ x ≤ .
2
(5)
π
(e) Find the solution of the equation csc 2x = 1.5 tan x – 0.5, 0 ≤ x ≤ .
2
(6)
(Total 21 marks)
36. In a triangle ABC, Â = 35°, BC = 4 cm and AC = 6.5 cm. Find the possible values of B̂ and
the corresponding values of AB.
(Total 7 marks)
(a) sin B;
(1)
(b) cos B;
(1)
3
39. Given that tan 2θ = , find the possible values of tan θ.
4
(Total 5 marks)
(a) Show that the equation 4 cos 2x + 3 sin x cosec3 x + 6 = 0 can be expressed as
8s4 – 10s2 + 3 = 0.
(3)
(b) Hence solve the equation for x, in the interval [0, π].
(6)
(Total 9 marks)
1
(b) Hence find the values of x between 0° and 360° when k = and α = 210°.
2
(6)
(Total 9 marks)
43. The lengths of the sides of a triangle ABC are x – 2, x and x + 2. The largest angle is 120°.
15 3
(b) Show that the area of the triangle is .
4
(3)
p q
(c) Find sin A + sin B + sin C giving your answer in the form where p, q, r .
r
(4)
(Total 13 marks)
44. A farmer owns a triangular field ABC. The side [AC] is 104 m, the side [AB] is 65 m and the
angle between these two sides is 60°.
(b) Find the area of the field in the form p 3 , where p is an integer.
(3)
Let D be a point on [BC] such that [AD] bisects the 60° angle. The farmer divides the field into
two parts by constructing a straight fence [AD] of length x metres.
65x
(c) (i) Show that the area o the smaller part is given by and find an expression for
4
the area of the larger part.