MathDB

11.3

Part of 2009 All-Russian Olympiad Regional Round

Problems(1)

xcos x <= pi^2/ 16 if x \in [0, \pi/2]

Source: All-Russian MO 2009 Regional 11. 3

8/28/2024
Prove that xcos⁡x≤π216x\cos x \le \frac{\pi^2}{16} for 0≤x≤π20 \le x \le \frac{\pi}{2}
algebrainequalitiestrigonometry