Try another version of this question
Write the product as a sum:
20sin(21c)cos(17c)=
20sin(21c)cos(17c)=
Get help:
Box 1: Enter your answer as an expression. Example: 3x^2+1, x/5, (a+b)/c
Be sure your variables match those in the question
10sin(38c)+10sin(4c)