原式=-∫arctanx d[1/(x-1)]=-arctanx /(x-1)+∫[1/(x-1)]*[1/(x²+1)]dx
=arctanx /(1-x) +∫(1/2)*[1/(x-1) -(x+1)/(x²+1)]dx
=arctanx /(1-x) +(1/2)∫dx/(x-1)-(1/2)∫[(x +1/2)/(x²+1)]dx-(1/4)∫dx/(x²+1)
=arctanx /(1-x) +ln√|x-1| -(1/4)ln(x²+1) -(1/4)arctanx +C
=[(x+3)/(4-4x)]*arctanx +ln√[|x-1|/√(x²+1)] +C