[微積] 請教一下這兩題

看板Math作者 (墮落研究生)時間8年前 (2016/06/24 16:01), 編輯推噓3(3推 0噓 3→)
留言6則, 1人參與, 最新討論串1/1
http://imgur.com/K9qozMO
如圖~請教一下這兩題微分方程式如何解~裡面的字寫錯了~不好意思 謝謝各位囉~ -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 1.165.110.233 ※ 文章網址: https://www.ptt.cc/bbs/Math/M.1466755309.A.3C7.html
推
06/24 18:11, , 1F
Let z=y' and u=z/x, then you will have u''=1/x^6
06/24 18:11, 1F
→
06/24 18:12, , 2F
solve for u, and you get expression for y.
06/24 18:12, 2F
→
06/24 18:12, , 3F
the above is for question 1.
06/24 18:12, 3F
推
06/24 18:14, , 4F
For question 2, first solve homegeneous equation
06/24 18:14, 4F
→
06/24 18:15, , 5F
y''+4y=0, this is easy.
06/24 18:15, 5F
推
06/24 18:21, , 6F
Sorry, for question 1 should be u''=x^(-7)
06/24 18:21, 6F
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