∵∫[xe^x/√(e^x-2)]dx
=∫x[1/√(e^x-2)]d(e^x-2)
=2∫xd[√(e^x-2)]
=2x√(e^x-2)-2∫√(e^x-2)dx.
∴令√(e^x-2)=u,则:x=ln(2+u^2),∴dx=2[u/(2+u^2)]du.
∴∫[xe^x/√(e^x-2)]dx
=2x√(e^x-2)-2∫u·2[u/(2+u^2)]du
=2x√(e^x-2)-4∫{[(2+u^2)-2]/(2+u^2)}du
=2x√(e^x-2)-4∫du+8∫[1/(2+u^2)]du
=2x√(e^x-2)-4u+8∫[1/(2+u^2)]du
=2x√(e^x-2)-4√(e^x-2)+8∫[1/(2+u^2)]du.
再令u=√2t,则:t=u/√2,du=√2dt.
∴∫[xe^x/√(e^x-2)]dx
=2x√(e^x-2)-4√(e^x-2)+8√2∫[1/(2+2t^2)]dt
=2x√(e^x-2)-4√(e^x-2)+4√2∫[1/(1+t^2)]dt
=2x√(e^x-2)-4√(e^x-2)+4√2arctant+C
=2x√(e^x-2)-4√(e^x-2)+4√2arctan(u/√2)+C
=2x√(e^x-2)-4√(e^x-2)+4√2arctan√[(1/2)e^x-1]+C.