解答题 7.求∫exsin2xdx.
【正确答案】∫exsin2xdx=
而∫excos 2xdx=∫cos2xdex
=excos 2x+2∫sin 2x.exdx
=excos 2x+2∫sin 2xdex=excos 2x+2exsin 2x一4∫excos 2xdx,
【答案解析】