### Calculus graphing. Urgent help appreciated!

A math student writes a proof of the derivative of a certain trigonometric function. The last line she writes before stating her conclusion is...

**d/d?(sin(?+?/2))=cos(?+?/2)**

These are the graphs of sin(?+?/2) and cos(?+?/2)

**sin(?+?/2)** = http://www.wolframalpha.com/input/?i=sin%28theta%2Bpi%2F2%29&lk=4

**cos(?+?/2)**= http://www.wolframalpha.com/input/?i=cos%28theta%2Bpi%2F2%29&lk=4&num=1

Hence, write the statement of her conclusion beginning with the word, "Therefore...".