设原函数是F(x)
则F(x)=∫(sinx)^5dx
=∫(sinx)^4*sinxdx
=-∫(sin²)²d(cosx)
=-∫(1-cos²x)²d(cosx)
=-∫(1-2cos²x+(cosx)^4)d(cosx)
记cosx=t
则F(x)=-∫(1-2t²+t^4)dt=-(t-2/3t^3+1/5t^5)+C=-t+2/3t^3-1/5t^5+C
则F(x)=-cosx+2/3(cosx)^3-1/5(cosx)^5+C
(5*cos(3x))/48 - cos(5x)/80 - (5*cos(x))/8