Which identity is most useful to evaluate ∫0π/2sinxsinx+cosxdx\int_0^{\pi/2} \frac{\sqrt{\sin x}}{\sqrt{\sin x} + \sqrt{\cos x}} dx∫0π/2sinx+cosxsinxdx?
∫0af(x)dx=∫0af(a−x)dx\int_0^a f(x) dx = \int_0^a f(a-x) dx∫0af(x)dx=∫0af(a−x)dx
Integration by parts
Partial fraction decomposition
Wallis's Formula