Trigonometrymedium · Past Paper
If tan A = 3/4, find the value of cos(2A).
A7/25
B24/25
C1/7
D7/24
✓ Correct Answer: A — 7/25
cos(2A) = (1 - tan^2 A) / (1 + tan^2 A) = (1 - 9/16) / (1 + 9/16) = 7/25.
Share this question
More from Trigonometry
- If tan θ = a/b, find the value of (cos θ + sin θ) / (cos θ - sin θ).
- If a bird is 40 m high and the angle of elevation from a boy is 30°, how far is the bird from the boy's eye?
- If sin(A+B) = 1 and cos(A-B) = √3/2, find A and B.
- If x = a cos theta and y = b sin theta, then b^2 x^2 + a^2 y^2 is equal to:
- The value of tan 0° is: