Re: [微積] 一題二重積分

[Indigoa (小彥oO)]

※ 引述《paggei (XD)》之銘言：
: ∫∫sin((x-y)/(x+y))dxdy, D是一四邊形區域 四頂點:(1,1) (2,2) (4,0) (2,0)
:  D
: 求解  不知道要從何下手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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