用分部积分
∫sin^3xdx=∫sin^2xdcosx=sin^2xcosx-∫cosxdsin^2x
=sin^2xcosx+∫2cos^2xsinxdx=sin^2xcosx+2∫cos^2xdcosx=sin^2xcosx+(4/3)cos^3x+dx
用分部积分
∫sin^3xdx=∫sin^2xdcosx=sin^2xcosx-∫cosxdsin^2x
=sin^2xcosx+∫2cos^2xsinxdx=sin^2xcosx+2∫cos^2xdcosx=sin^2xcosx+(4/3)cos^3x+dx