Câu hỏi 99
Cho hàm tăng $f:[0,\pi/2]\to[0,\infty)$. Chứng minh:
a) $\displaystyle\int_0^{\pi/2}(f(x)-f(\pi/4))(\sin x-\cos x)\,dx\ge0$.
a) $\displaystyle\int_0^{\pi/2}(f(x)-f(\pi/4))(\sin x-\cos x)\,dx\ge0$.
MathNet 2013 Câu hỏi 99
Math Olympiad Vault · MathNet 2013