one integration
回答 (1)
2013-10-22 9:52 pm
✔ 最佳答案
Let y = 1/x, dy = (-1/x^2) dx{ [e^(1/x) / x^4] dx
= - { [(1/x)^2 e^(1/x) (-1/x^2)] dx
= - { [y^2 e^y] dy
= - [y^2 e^y] + { [2y e^y] dy
= - [y^2 e^y] + [2y e^y] - { [2e^y] dy
= - [y^2 e^y] + [2y e^y] - [2e^y] + C
= (- y^2 + 2y - 2)e^y + C
= (- 1/x^2 + 2/x - 2)e^(1/x) + C
參考: knowledge
收錄日期: 2021-04-28 14:22:03
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20131022000051KK00061