Trigonometrymedium · Past Paper
If sin A = 4/5, find sin(2A).
A8/5
B24/25
C12/25
D6/5
✓ Correct Answer: B — 24/25
cos A = 3/5. sin(2A) = 2 sin A cos A = 2 * (4/5) * (3/5) = 24/25.
Share this question
More from Trigonometry
- What is the value of tan 9° - tan 27° - tan 63° + tan 81°?
- Find the height of a tower if its shadow is 20√3 m long when the sun's elevation is 30°.
- A man in a boat moving away from a cliff 100 m high takes 2 mins for elevation to change from 60 to 30. Speed?
- Simplify: sin A / (1 - cos A) if A is in the first quadrant.
- The identity cos^2(theta) = 1 - ...?