Question

Let D be the elliptical region given finalized_jax">x"src="http://latex.codecogs.com/gif.latex?%3Cspan+class%3D%22MathJax%22%3E%3Cspan+class%3D%22math%22%3E%3Cspan+style%3D%22width%3A5.185em%3Bheight%3A0px%3Bfont-size%3A135%25%3B%22%3E%3Cspan%3E%3Cspan+class%3D%22mrow%22%3E%3Cspan+class%3D%22msubsup%22%3E%3Cspan+style%3D%22width%3A1.076em%3Bheight%3A0px%3B%22%3E%3Cspan%3E%3Cspan+class%3D%22mi%22+style%3D%22font-style%3Aitalic%3B%22%3Ex"/> Compute

finalized_jax">∫"src="http://latex.codecogs.com/gif.latex?%3Cspan+class%3D%22MathJax%22%3E%3Cspan+class%3D%22math%22%3E%3Cspan+style%3D%22width%3A4.506em%3Bheight%3A0px%3Bfont-size%3A135%25%3B%22%3E%3Cspan%3E%3Cspan+class%3D%22mrow%22%3E%3Cspan+class%3D%22texatom%22%3E%3Cspan+class%3D%22mrow%22%3E%3Cspan+class%3D%22msubsup%22%3E%3Cspan+style%3D%22width%3A.679em%3Bheight%3A0px%3B%22%3E%3Cspan%3E%3Cspan+class%3D%22mo%22+style%3D%22vertical-align%3A0em%3B%22%3E%C3%A2%CB%86%C2%AB"/> By change of variables finalized_jax">x"src="http://latex.codecogs.com/gif.latex?%3Cspan+class%3D%22MathJax%22%3E%3Cspan+class%3D%22math%22%3E%3Cspan+style%3D%22width%3A2.84em%3Bheight%3A0px%3Bfont-size%3A135%25%3B%22%3E%3Cspan%3E%3Cspan+class%3D%22mrow%22%3E%3Cspan+class%3D%22mi%22+style%3D%22font-style%3Aitalic%3B%22%3Ex"/> and finalized_jax">y"src="http://latex.codecogs.com/gif.latex?%3Cspan+class%3D%22MathJax%22%3E%3Cspan+class%3D%22math%22%3E%3Cspan+style%3D%22width%3A2.716em%3Bheight%3A0px%3Bfont-size%3A135%25%3B%22%3E%3Cspan%3E%3Cspan+class%3D%22mrow%22%3E%3Cspan+class%3D%22mi%22+style%3D%22font-style%3Aitalic%3B%22%3Ey"/>

The answer is finalized_jax">6"src="http://latex.codecogs.com/gif.latex?%3Cspan+class%3D%22MathJax%22%3E%3Cspan+class%3D%22math%22%3E%3Cspan+style%3D%22width%3A1.049em%3Bheight%3A0px%3Bfont-size%3A135%25%3B%22%3E%3Cspan%3E%3Cspan+class%3D%22mrow%22%3E%3Cspan+class%3D%22mn%22%3E6"/> but i don't understand how to get there by thismethod

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