IMO Shortlist 1967 problem 3
Dodao/la:
arhiva2. travnja 2012. Prove the trigonometric inequality
![\displaystyle \cos x < 1 - \frac{x^2}{2} + \frac{x^4}{16},](/media/m/b/c/1/bc117216b0d4f6c164efae51f266b762.png)
when
%V0
Prove the trigonometric inequality $\displaystyle \cos x < 1 - \frac{x^2}{2} + \frac{x^4}{16},$ when $\displaystyle x \in \left(0, \frac{\pi}{2} \right)\text{.}$
Izvor: Međunarodna matematička olimpijada, shortlist 1967