[tex]\displaystyle\int_{y=0}^{y=1}\int_{x=8y}^{x=8}e^{x^2}\,\mathrm dx\,\mathrm dy[/tex]
[tex]=\displaystyle\int_{x=0}^{x=8}\int_{y=0}^{y=x/8}e^{x^2}\,\mathrm dy\,\mathrm dx[/tex]
[tex]=\displaystyle\frac18\int_{x=0}^{x=8}xe^{x^2}\,\mathrm dx[/tex]
[tex]=\displaystyle\frac1{16}\int_{x=0}^{x=8}2xe^{x^2}\,\mathrm dx[/tex]
[tex]=\displaystyle\frac1{16}\int_{x=0}^{x=8}e^{x^2}\,\mathrm d(x^2)[/tex]
[tex]=\dfrac{e^{64}-1}{16}[/tex]
