Write the expression as a single Runctiblt of a
\[
\cos \left(90^{\circ}-a\right)
\]
Choose the corred answer below.
A. $-\sin \alpha$
B. $-\cos \alpha$
C. $\sin \alpha$
D. $\cos \alpha$

Answer

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Answer

Final Answer: The correct answer is $\boxed{\sin \alpha}$

Steps

Step 1 ：Write the expression as a single function of a: $\cos (90^{\circ}-a)$

Step 2 ：Choose the correct answer below.

Step 3 ：Final Answer: The correct answer is $\boxed{\sin \alpha}$