Ondivinding(x2+1)by(x2+2x+1),weget(x2+1)(x+1)2={1−2x(x+1)2}Let2x(x+1)2=A(x+1)+B(x+1)22x=A(x+1)+B.−−−−(1)Onequatingthecoefficientsofx,wegetA=2Onequatingconstantterm,wegetA+B=0⇒B=−A=−2∴2x(x+1)2=2(x+1)−2(x+1)2∴I=∫{1−2x(x+1)2}=∫{1−2(x+1)+2(x+1)2}dxx−2log|x+1|−2(x+1)+C.