Simplify .
Answer and explanation
Correct answer: A.
- Step 1: Co-function identity: sin(90° - θ) = cos θ.
Answer
.
Why not the others: : the co-function identity swaps sine and cosine. : 90° - θ lies in the first quadrant for acute θ, so the sign is positive. : the sign is positive for acute θ and the ratio changes.
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