Homework Statement
Prove that
sin(5A)+sin(2A)-sin(A) = sin(2A)*(2*cos(3A)+1)Homework Equations
sin(2A) = 2(sin(A)cos(A))
cos(2B) = cos2(A)-sin2(A)
cos(A+B) = cos(A)cos(B) - sin(A)sin(B)
sin(A+B) = sin(A)cos(B) + sin(B)cos(A)
The Attempt at a Solution
I can't find any other way than to just...