求cosx五次方的不定积分

求cosx五次方的不定积分

∫(cosx)^5dx =∫(cosx)^4*cosxdx =
=∫(cosx)^4*dsinx =∫[(cosx)^2]^2*dsinx =
=∫[1-(sinx)^2]^2*dsinx =∫[1-2(sinx)^2+(sinx)^4]*dsinx =
=sinx-(2/3)(sinx)^3+(1/5)(sinx)^5+C.