作者Indigoa (小彦oO)
看板Math
标题Re: [微积] 一题二重积分
时间Sat Mar 19 19:17:47 2011
※ 引述《paggei (XD)》之铭言：
: ∫∫sin((x-y)/(x+y))dxdy, D是一四边形区域 四顶点:(1,1) (2,2) (4,0) (2,0)
: D
: 求解 不知道要从何下手QQ
Let x-y=u x+y=v => x=u+v/2 y=-u+v/2
Choose some points in the x-y plane so that you can get a new reigon on the
u-v plane which is bounded by lines (S) :
(1)v=2
(2)v=4
(3)u=0
(4)u=v
And calculate the determinant of Jacobian |J|u,v||=1/2
Then you can get ∫∫sin(u/v) dudv
S
Calculus your answer simply XD...
I can't type Chinsese =^=...
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1F：→ Indigoa :可以打中文噜..看不懂请见谅 最後一个式子少打1/2~ 03/19 19:18