Trigonometryhard · Past Paper
If a cos theta - b sin theta = c, find the value of a sin theta + b cos theta.
Asqrt(a^2 + b^2 + c^2)
Bsqrt(a^2 + b^2 - c^2)
Ca + b - c
Dsqrt(c^2 - a^2 - b^2)
✓ Correct Answer: B — sqrt(a^2 + b^2 - c^2)
(a cos - b sin)^2 + (a sin + b cos)^2 = a^2 + b^2. So c^2 + x^2 = a^2 + b^2, x = sqrt(a^2 + b^2 - c^2).
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