- #1
Hernaner28
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Homework Statement
Integrate:
[tex] \displaystyle f\left( x,y \right)=\frac{{{x}^{2}}}{{{x}^{2}}+{{y}^{2}}}[/tex]
on the region:
[tex] \displaystyle D=\left\{ \left( x,y \right)\in {{\mathbb{R}}^{2}}:0\le x\le 1,{{x}^{2}}\le y\le 2-{{x}^{2}} \right\}[/tex]
TIP: Use change of coordinates:
[tex] \displaystyle x=\sqrt{v-u}[/tex]
[tex] \displaystyle y=v+u[/tex]
Homework Equations
The Attempt at a Solution
Alright, what I did was to sketch the two regions. After that I calculated the jacobian of the change of coordinates function:
[tex] \displaystyle g\left( u,v \right)=\left( \sqrt{v-u},v+u \right)[/tex]
[tex] \displaystyle \left| Jg \right|=\frac{1}{\sqrt{v-u}}[/tex]
So the new integral becomes
[tex] \displaystyle \int\limits_{0}^{1}{\int\limits_{u}^{1}{\frac{v-u}{v-u+{{\left( u+v \right)}^{2}}}\cdot \frac{1}{\sqrt{v-u}}dv}du}=\int\limits_{0}^{1}{\int\limits_{u}^{1}{\frac{\sqrt{v-u}}{v-u+{{\left( u+v \right)}^{2}}}dv}du}[/tex]
And here I'm stuck. I don't know how to continue. I don't like the integrand. Any help?
Thanks!