Quandaries
and Queries 

Who is asking: Student Level: Secondary Question: "Express sin3A in terms of sinA and cosA." I can only get work it out so far and then I end up back where I began. Any thoughts or clues to a solution would be greatly appreciated. 

Hi, Write 3A as 2A + A to get
and then use the multiple angle expression for the sine.
Now write 2A as A + A
Finally expand sin(A + A) and cos(A + A) using the multiple angle expressions for sine and cosine. Penny 

