Tích phân \(\int\limits^{\frac{\pi}{2}}_0\sin\left(\dfrac{\pi}{4}-x\right)\text{d}x\) bằng
\(\sqrt{2}\).\(0\).\(-\sqrt{2}\).\(1\).Hướng dẫn giải:Có \(\int\sin\left(\dfrac{\pi}{4}-x\right)\text{d}x=\int-\sin\left(\dfrac{\pi}{4}-x\right)\text{d}\left(\dfrac{\pi}{4}-x\right)=\cos\left(\dfrac{\pi}{4}-x\right)+C\) nên \(\int\limits^{\frac{\pi}{2}}_0\sin\left(\dfrac{\pi}{4}-x\right)\text{d}x=\cos\left(\dfrac{\pi}{4}-x\right)|^{\frac{\pi}{2}}_0=0.\)