Trigonometry · Guided Practice

Trigonometry

27 questions with answers and video solutions. Try each one before revealing the answer.

1
Find the exact value of cos75\displaystyle \cos 75^\circ.
Video solution coming soon
2
Find the exact value of sin195\displaystyle \sin 195^\circ.
Video solution coming soon
3
Given that sinx=513,0<x<π2\displaystyle \sin x=\frac{5}{13},\,0 < x < \frac{\pi}{2}, find the exact value of sin2x\displaystyle \sin 2x.
Video solution coming soon
4
An angle x\displaystyle x is such that 0<x<π4\displaystyle 0 < x < \frac{\pi}{4} and tan2x=43\displaystyle \tan 2x=\frac{4}{3}.
(a) Find the exact value of cos2x\displaystyle \cos 2x.
(b) Hence find the exact value of cosx\displaystyle \cos x.
Video solution coming soon
5
Given that cos2x=1213,0<x<π4\displaystyle \cos 2x=\frac{12}{13},\,0 < x < \frac{\pi}{4}, find the exact value of tanx\displaystyle \tan x.
Video solution coming soon
6
Given that 0<x<45\displaystyle 0 < x < 45^\circ and sinx=35\displaystyle \sin x=\frac{3}{5}, determine the exact values of:
(a) cosx\displaystyle \cos x
(b) sin2x\displaystyle \sin 2x
(c) cos2x\displaystyle \cos 2x
(d) cos3x\displaystyle \cos 3x
(e) sin3x\displaystyle \sin 3x.
Video solution coming soon
7
Solve cos2x=sinx\displaystyle \cos 2x=\sin x for 0x<2π\displaystyle 0\leqslant x < 2\pi.
Video solution coming soon
8
Solve 2cos2x+1=0\displaystyle 2\cos 2x^\circ+1=0 for 0x<360\displaystyle 0\leqslant x < 360.
Video solution coming soon
9
Solve 2cos2x=1\displaystyle 2\cos^2 x^\circ=1 for 0x<360\displaystyle 0\leqslant x < 360.
Video solution coming soon
10
2019 P1 Q15
(4, 1)5 Marks

(a)  Solve the equation
sin2x+6cosx=0\displaystyle \sin 2x^{\circ}+6\cos x^{\circ}=0
for 0x<360.\displaystyle 0\le x \lt 360.
(b)  Hence solve
sin4x+6cos2x=0\displaystyle \sin 4x^{\circ}+6\cos 2x^{\circ}=0
for 0x<360.\displaystyle 0\le x \lt 360.

11
2021 P2 Q8
Solve the equation 2sin(3x60)+1=0,0x<180\displaystyle 2\sin(3x-60)^\circ+1=0,\:0\leqslant x < 180.
Video solution coming soon
12
2023 P2 Q7
5 Marks
Solve the equation
sinx+2=3cos2x\displaystyle \sin x^{\circ}+2=3\cos 2x^{\circ}
for 0x<360.\displaystyle 0\le x \lt 360.
13
Express 3cosx+sinx\displaystyle \sqrt{3}\cos x^\circ+\sin x^\circ in the form kcos(xa)\displaystyle k\cos(x-a)^\circ where k>0\displaystyle k > 0 and 0<a<360\displaystyle 0 < a < 360.
Video solution coming soon
14
Express 2cosx3sinx\displaystyle 2\cos x^\circ-3\sin x^\circ in the form kcos(xa)\displaystyle k\cos(x-a)^\circ where k>0\displaystyle k > 0 and 0<a<360\displaystyle 0 < a < 360.
Video solution coming soon
15
Express 5sinx2cosx\displaystyle 5\sin x^\circ-2\cos x^\circ in the form kcos(x+a)\displaystyle k\cos(x+a)^\circ where k>0\displaystyle k > 0 and 0<a<360\displaystyle 0 < a < 360.
Video solution coming soon
16
Express sinx3cosx\displaystyle \sin x-\sqrt{3}\cos x in the form ksin(x+a)\displaystyle k\sin(x+a) where k>0\displaystyle k > 0 and 0<a<2π\displaystyle 0 < a < 2\pi.
Video solution coming soon
17
Express 2sinx+7cosx\displaystyle -2\sin x+7\cos x in the form ksin(xa)\displaystyle k\sin(x-a) where k>0\displaystyle k > 0 and 0<a<2π\displaystyle 0 < a < 2\pi.
Video solution coming soon
18
(a) Express 3cosx+sinx\displaystyle 3\cos x^\circ+\sin x^\circ in the form kcos(xa)\displaystyle k\cos(x-a)^\circ where k>0\displaystyle k > 0 and 0<a<360\displaystyle 0 < a < 360.
(b) State the maximum value of 3cosx+sinx\displaystyle 3\cos x^\circ+\sin x^\circ and find the value of 0x<360\displaystyle 0\leqslant x < 360 at which it occurs.
(c) State the minimum value of 3cosx+sinx\displaystyle 3\cos x^\circ+\sin x^\circ and find the value of 0x<360\displaystyle 0\leqslant x < 360 at which it occurs.
Video solution coming soon
19
Solve 3cosx+2sinx=1\displaystyle -3\cos x^\circ+2\sin x^\circ=-1, where 0x<360\displaystyle 0\leqslant x < 360.
Video solution coming soon
20
Solve 5sin2x4cos2x=3\displaystyle 5\sin 2x-4\cos 2x=3, where 0x<2π\displaystyle 0\leqslant x < 2\pi.
Video solution coming soon
21
2018 Spec P2 Q11
Show that sin2x2cosxsinxcos2x=sin3x\displaystyle \frac{\sin 2x}{2\cos x} - \sin x\cos^2 x = \sin^3 x, where 0<x<π2\displaystyle 0 < x < \frac{\pi}{2}.
Video solution coming soon
22
2024 P2 Q12
5 Marks
Solve the equation
2sin2xsin2x=0\displaystyle 2 \sin 2x^{\circ}-\sin^{2}x^{\circ} = 0
for 0x<360\displaystyle 0\le x \lt 360.
23
2025 P2 Q11
4 Marks
Solve
3 sin 2x+4 cos x=0\displaystyle 3~\sin~2x^{\circ}+4~\cos~x^{\circ}=0
for 0x<360\displaystyle 0\le x \lt 360.
24
2026 P1 Q4
(1, 4, 2, 1)8 Marks

The diagram shows two right-angled triangles with angles p and q as marked.

Two right-angled triangles, one with sides 3 and 4 and angle p, the other with sides 13 and angle q

(a)  Determine the exact value of sinq.\displaystyle \sin q.
(b)  Find the exact value of:
    (i)  sin(p+q)\displaystyle \sin(p+q)
    (ii)  cos(p+q).\displaystyle \cos(p+q).
(c)  Hence find the exact value of tan(p+q).\displaystyle \tan(p+q).

25
2026 P2 Q10
5 Marks
Solve the equation 3cos2x+10cosx=1\displaystyle 3\cos 2x^{\circ}+10\cos x^{\circ}=1 for 0x<360.\displaystyle 0\le x \lt 360.
26
2026 P2 Q13
(4, 3)7 Marks

(a)  Express 2sinx7cosx\displaystyle 2\sin x^{\circ}-7\cos x^{\circ} in the form ksin(xa)\displaystyle k\sin(x-a)^{\circ}, where k>0\displaystyle k \gt 0 and 0<a<360.\displaystyle 0 \lt a \lt 360.
The diagram shows part of the curve with equation y=2sinx7cosx\displaystyle y=2\sin x^{\circ}-7\cos x^{\circ} and the line with equation y=3.\displaystyle y=3.
The curve and the line intersect at the point P.

Curve y = 2 sin x - 7 cos x meeting the line y = 3 at the point P

(b)  Find the x-coordinate of P.

27
2026 P2 Q15
3 Marks
Express (3sinθ+cosθ)(sinθ+3cosθ)\displaystyle (3\sin\theta+\cos\theta)(\sin\theta+3\cos\theta) in the form a+bsincθ\displaystyle a+b\sin c\theta, where a, b and c are integers.

Practice questions courtesy of Maths.scot. Full written solutions are on his site — the links above go straight to them.