∫0π/2sin2x dx=\displaystyle \int_0^{\pi/2} \sin^2 x \, dx =∫0π/2sin2xdx=Aπ4\frac{\pi}{4}4πcheck_circleBπ2\frac{\pi}{2}2πCπ8\frac{\pi}{8}8πD111Explanationsin2x=(1−cos2x)/2\sin^2 x = (1-\cos 2x)/2sin2x=(1−cos2x)/2, so the integral equals [x/2−(sin2x)/4]0π/2=π/4[x/2 - (\sin 2x)/4]_0^{\pi/2} = \pi/4[x/2−(sin2x)/4]0π/2=π/4.