解:由(cosx)'=-sinx可得:d(cosx)=-sinxdx所以:
∫(sinx)^5*dx
=∫(1-(cosx)^2)^2sinxdx
=-∫(1-(cosx)^2)^2d(cosx)
=-∫[1-2(cosx)^2+(cosx)^4]d(cosx)
=-cosx+(2/3)(cosx)^3-(1/5)(cosx)^5+C
∫(sinx)^5 dx
=∫(sinx)(1-(cosx)^2)^2dx
=-∫(1-(cosx)^2)^2dcosx
=-∫(t^2-1)^2dt
=-∫t^4-2t^2+1dt
=-t^5/5+2t^3/3-t+C
=...
∫(sinx)^5*dx
=-∫(sinx)^4*dcosx
=-∫[1-(cosx^2)]^2*dcosx
=-(cosx)^5/5+2*(cosx)^3/3-cosx+c