1. The problem statement, all variables and given/known data show that sin4x + 2sin2x = 8sinxcos^3x 2. Relevant equations sin2x =2sinxcosx 3. The attempt at a solution I started out by letting sin4x = sin(2x*2) so that I could plugg in sin2x = 2sinxcosx in the equation. sin(2x*2) +2sin2x = sin2*sin2x +2sin2x = sin2 * (2sinxcosx) + 2*sin2x = sin2* (2sinxcosx) + 2* (2sinxcosx) and I end up with 8sinxcosx which is wrong! ??