f(x)的导数=xsinx ,求f(x)
问题描述：
f(x)的导数=xsinx ,求f(x)
答
f(x)=sinx-xcosx
答
f(x) =∫xsinx dx
=-xcosx+∫cosx dx
=-xcosx+sinx+c
答
f(x)=∫xsinxdx
=-∫x dcosx
=-xcosx+∫sinxdx
=-xcosx-cosx+c(常数)
用的是分部积分法.