EASY
AS and A Level
IMPORTANT
Earn 100

Express sin 3θ and cos 2θ in terms of sin θ.Hence show that sin 18° is a root of the equation 4x3-2x2-3x+1=0.

Important Questions on Trigonometry

EASY
AS and A Level
IMPORTANT
Find the exact value of sin 18°.Given that sin 18° is a root of the equation 4x3-2x2-3x+1=0.
EASY
AS and A Level
IMPORTANT
Find the range of values of θ between 0 and 2π for which cos 2θ>cos θ.
EASY
AS and A Level
IMPORTANT
Solve the inequality cos 2θ-3 sin θ-20 for 0°θ360°.
EASY
AS and A Level
IMPORTANT
 Use the expansions of cos(2x+x) and cos(2x-x), to prove that: cos 3x+cos x2 cos 2x cos x
EASY
AS and A Level
IMPORTANT

 Use the expansions of cos(2x+x) and cos(2x-x), to prove that: cos 3x+cos x2 cos 2x cos x 

Solve cos 3x+cos 2x+cosx>0 for 0°<x<360°.

EASY
AS and A Level
IMPORTANT
Solve the inequality cos 4θ+3 cos 2θ+1<0 for 0°θ360°.
EASY
AS and A Level
IMPORTANT

Prove each of these identities. tan A+cot A2cosec2A