作者wrbyonex (间波)
看板Math
标题[微积] Integration by parts?
时间Mon Feb 7 18:21:24 2011
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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1F：→ sm008150204 :如果是我会用三角积分耶 Let x=tan(u)要不要这样试试 02/07 18:39
2F：→ sm008150204 :算出来是1/8(x sqrt(x^2+1) (2x^2-3)+3sinh^(-1)(x)) 02/07 18:49
3F：→ wrbyonex :我就是用你的方法啊？可是後面的我又不知道怎算了 02/07 21:49
4F：→ wrbyonex :我是先变数变换再用分部积分 02/07 21:50
6F：→ wrbyonex :算出来了，谢谢！ 02/08 20:39