Answer: 3sinA - 4sin³A.
- A 3sinA - 4sin³A
- B 4sinA - 3sin³A
- C 3sinA + 4sin³A
- D sin³A + 3sinA
Correct answer: A. 3sinA - 4sin³A
Explanation: sin 3A = 3 sinA - 4 sin³A. (Standard triple angle formula).
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