=∫1/((x+i)(x-i))dx
=(1/2)∫(1/x+i)+(1/x-i)dx
错了
1/(x+i)+1/(x-i)
=(x+i+x-i)/(x+i)(x-i)
=2x/(x+i)(x-i)
不是2/(x+i)(x-i)