Question

不定积分分部积分法xtan方xdx

Answer 1

∫x(tanx)^2dx =∫x[(secx)^2-1]dx =∫x(secx)^2dx -∫xdx
=∫xdtanx - x^2/2 = xtanx -∫tanxdx - x^2/2
= xtanx +ln|cosx| - x^2/2 + C.