How to create own transformation change of variables

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Evaluate the following integral using change of variables. Draw the original and new regions of integration.

$$\int\int_{R} \frac{1}{x^2-y^2} dA$$

where R is bounded by the lines

$x + y = 1 ,x + y = e, x − y = 1, x − y = e$

I am used to seeing problems where the desired transformation is given, but I don't understand how to make my own region. Are the new regions simply the partial derivatives of the region given?

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"partial derivatives of the region given" doesn't make sense.

But what does make sense is to use the form of $x$ and $y$ given for the region. That is, try $u = x + y$ and $v =x - y$. Then the region in the new coordinates is just $1 \rightarrow e$ for both.

Note also that $uv = x^2 - y^2$. Can you take it from there?