Question

Which sum or difference identity would you use to verify that sin (90° + q) = cos q?

Answer 1

`\hbox{the sum identity:} \\ \sin(\alpha + \beta)= \sin \alpha \cos \beta + \sin \beta \cos \alpha \\ \\ \sin (90^\circ +q)= \\ \sin 90^\circ \cos q+ \sin q \cos 90^\circ= \\ 1 * \cos q + \sin q * 0= \\ \cos q`

Answer 2

Option B is your answer

Explanation: