prove that cosx-cosx sin^2x = cos^3x

Question

 Proving a trig identity and I dont know what to do 

Answer 1

prove:

cosx-cosxsin^2x=cos^3x

factor

cosx(1-sin^2x)=cos^3x

cosx(cos^2x)=cos^3x  because sin^2x+cos^2x=1 and cos^2x=1-sin^2x

cos^3x=cos^3x