Sin^3(a)*cos(a)-sin(a)*cos^3(a)

Question

Sin^3(a)*cos(a)-sin(a)*cos^3(a)

Answer 1

=sin(a)cos(a) [sin^2(a) -cos^2(a)] =1/2sin 2a(-cos2a)=-1/2sin2acos2a=-1/4sin4a