Trigonometryhard · Past Paper
If A+B+C = 180, then sin^2 A + sin^2 B - sin^2 C = ?
A2 sin A sin B cos C
B2 cos A cos B sin C
C1 - 2 sin A sin B cos C
D0
✓ Correct Answer: A — 2 sin A sin B cos C
Standard conditional identity for sine squares in a triangle.
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