Chapter 5.6, Problem 26MP

As needed, use a computer to plot graphs and to check values of integrals.

Make the change of variables $u=x-y,\text{}v=x+y$, to evaluate the integral ${\displaystyle {\int }_0^{1}dy}{\displaystyle {\int }_0^{1-y}{e}^{\left(x-y\right)/\left(x+y\right)}dx}$