Trigonometrymedium · Past Paper
If x = a cos theta and y = b sin theta, then b^2 x^2 + a^2 y^2 is equal to:
Aab
Ba^2 b^2
Ca^2 + b^2
D1
✓ Correct Answer: B — a^2 b^2
b^2(a^2 cos^2) + a^2(b^2 sin^2) = a^2 b^2 (cos^2 + sin^2) = a^2 b^2.
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