∫1/x^2-2x-3 dx 答案是1/4ln绝对值(x-3/x+1) +c

问题描述:

∫1/x^2-2x-3 dx 答案是1/4ln绝对值(x-3/x+1) +c

原式=∫dx/(x+1)(x-3)
=1/4∫[1/(x-3)-1/(x+1)]dx
=1/4[ln|x-3|-ln|x+1|]+C
=1/4*ln|(x-3)/(x+1)|+C