Trigonometrymedium · Past Paper
Simplify: sin A cos A cos 2A.
A1/2 sin 4A
B1/4 sin 4A
Csin 4A
D1/4 cos 4A
✓ Correct Answer: B — 1/4 sin 4A
sin A cos A = 1/2 sin 2A. Thus, 1/2 sin 2A cos 2A = 1/4 sin 4A.
Share this question
More from Trigonometry
- A ladder rests against a wall at α to the horizontal. Its foot is pulled a distance 'a' away so it slides 'b' down the wall, making angle β. Find a/b.
- The expression (tan θ + sec θ - 1) / (tan θ - sec θ + 1) is equal to:
- What is the value of cos 30°?
- Two poles of equal heights are standing opposite to each other on either side of a 100 m road. From a point between them, the elevations are 30° and 60°. Find the pole height.
- An observer 1.5 m tall is 20.5 m away from a tower 22 m high. What is the angle of elevation?