[微積] Integration by parts?

[wrbyonex (間波)]

int x^4/sqrt(1+x^2) dx from 0 to x

I use x=tany, but I failed for calculating the second term.

Any help would be appreciated.

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→ sm008150204 :如果是我會用三角積分耶 Let x=tan(u)要不要這樣試試
→ sm008150204 :算出來是1/8(x sqrt(x^2+1) (2x^2-3)+3sinh^(-1)(x))
→ wrbyonex    :我就是用你的方法啊？可是後面的我又不知道怎算了
→ wrbyonex    :我是先變數變換再用分部積分
推 sm008150204 :看看這個吧 http://ppt.cc/V@97
→ wrbyonex    :算出來了，謝謝！