Whoever gave you this problem expects you to know that sin(A+ B)= sin(A)cos(B)+ cos(A)sin(B) as well as \(\displaystyle sin^2(x)+ cos^2(x)= 1\).
(Because there are many different angles having the same sine and cosine, there will be more than one answer unless you are restricting A and B to be, say, acute angles.)
