Question

x/sin^2x的不定积分

Answer 1

∫xsin^2xdx
=∫xcsx^2xdx
=-∫xd(cotx)
=-xcotx-∫cotxdx
=-xcotx-∫cosxdx/sinx
=-xcotx-∫d(sinx)/sinx
=-xcotx-lnsinx+c.