作者aacvbn ( ︿(*￣︶￣*)︿)
看板trans_math
标题Re: [微分] 隐函数?
时间Sat Jul 1 23:27:58 2006
: 原题是 y^3-xy^2+cos(xy)=2 dy/dx at the point (0,1)
3 2 dy
y - xy + cos(xy) = 2 求 ---- at the point (0，1)
dx
(sol)
by Implicit Differentiation
d 3 2 d
--- (y -xy + cos(xy)) = --- (2)
dx dx
2 dy 2 dy dy
=> 3y‧ --- - y - 2xy--- - sin(xy)*(y+x ---) = 0
dx dx dx
2
dy y + ysin(xy)
=> ---- = ------------------
dx 2
3y - 2xy -xsin(xy)
令(x，y)=(0，1)代入上式
dy 1
--- = -----
dx 3
--
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1F：推 pcedison:很仔细 谢谢你 218.165.110.94 07/01 23:35
2F：推 geniusjimmy:感恩! 终於看懂了 <(_ _)> 163.23.6.76 07/01 23:44