原式=∫e^2x-1/(e^x+1)e^x\de^x
=∫(e^x-1)(e^x+1)/(e^x+1)e^x\de^x
=∫(e^x-1)/e^x\de^x
=∫[1-1/e^x]\de^x
=e^x-∫(1/e^x)\de^x
=e^x-x
想复杂了
原式=∫e^2x-1/(e^x+1)\dx =∫(e^x-1)(e^x+1)/(e^x+1)\dx =∫(e^x-1）\dx =e^x-x