Rewrite as a sum?

Rewrite as a sum: 6(sin 5theta) cos 2 theta

1 Answer
Mar 14, 2018

rarr6sin5x*cos2x=3sin7x+3sin3x

Explanation:

Use rarr2sinA*cosB=sin(A+B)+sin(A-B)

rarr6sin5x*cos2x

=3*[2sin5x*cos2x]

=3*[sin(5x+2x)+sin(5x-2x)]

=3*[sin7x+sin3x]=3sin7x+3sin3x