[微分] 問題請教...

看板trans_math作者 (victor)時間17年前 (2008/11/09 00:17), 編輯推噓2(203)
留言5則, 1人參與, 最新討論串1/2 (看更多)
1. Find A and B given that the function f(x) = { x^3 , x 小於等於1 { Ax +B , x> 1 2.Find conditions on a,b,c,d which guarantee that the graph of the cubic p(x)=ax^3+bx^2+cx+d (1.) exactly two horizontal tangents. 2 2 3.Express d y/d x (a) 4tany = x^3 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 140.123.221.147

11/11 00:11, , 1F
3.4tany = x^3 => y=arctan(x^3/4)...總之容
11/11 00:11, 1F

11/11 00:11, , 2F
易看出y是x的函數
11/11 00:11, 2F

11/11 00:40, , 3F
或者先一次微分=>4sec^2y*y'=3x^2=>再利用平
11/11 00:40, 3F

11/11 00:41, , 4F
方關係sec^2y=1+tan^2y=1+(x^3/4)^2可整理出
11/11 00:41, 4F

11/11 00:41, , 5F
y'是x的函數即可再微分一次...
11/11 00:41, 5F
文章代碼(AID): #195RkR2J (trans_math)
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文章代碼(AID): #195RkR2J (trans_math)