1．∫(x^2 +2)dx/(x+1)^3＝∫(1/(x+1))dx-2∫(1/(x+1)^2)dx+3∫(1/(x+1)^3)dx
所以∫(x^2 +2)dx/(x+1)^3＝ln(x+1)+2/(x+1)-(3/2)/(x+1)^2
2．x/(x-lnx)
不好意思,2是目测的