Answer: −3/4.
- A 3/4
- B −3/4
- C 1/4
- D −1/4
Correct answer: B. −3/4
Explanation: Squaring: 1 + sin2θ = 1/4, so sin2θ = −3/4.
Unit circle with standard angles 0, 30, 45, 60, 90 degrees; at 45 degrees the point is (cos45, sin45) = (1/sqrt2, 1/sqrt2).
Concept context
Ratios, identities, and applications in triangles