Answer
$(\frac{\pi{\sqrt 2-4}}{4(\sqrt 2-1)}, \frac{1}{4(\sqrt 2-1)})$
Work Step by Step
$M_{x}$ = $\frac{1}{2}\int_0^{\frac{\pi}{4}}(cos^{2}x-sin^{2}x)dx$ = $\frac{1}{4}$
$M_{y}$ = $\int_0^{\frac{\pi}{4}}x(cosx-sinx)dx$ = $\frac{\pi{\sqrt 2}}{4}-1$
$A$ = $\int_0^{\frac{\pi}{4}}(cosx-sinx)dx$ = $\sqrt 2-1$
so the coordinates of the centroid are
$(\frac{\pi{\sqrt 2-4}}{4(\sqrt 2-1)}, \frac{1}{4(\sqrt 2-1)})$