不定积分分子是dx分母是(x+1)(x-2)求解.

题目

不定积分分子是dx分母是(x+1)(x-2)求解.
help...help

答案

1/(x+1)/(x-2)
=1/3*[(x+1)-(x-2)]/(x+1)/(x-2)
=1/3*[1/(x-2)-1/(x+1)]
所以原式=1/3*(ln|x-2|-ln|x+1|)+C
=1/3ln|(x-2)/(x+1)|+C