If $0<x<\frac{\pi}{2}$, then

$\cos x>1-\frac{2 x}{\pi}$ $\cos x<1-\frac{2 x}{\pi}$ $\cos x>\frac{2 x}{\pi}$ $\cos x<\frac{2 x}{\pi}$

$\cos x>1-\frac{2 x}{\pi}$

It is evident from the graphs of the functions $y=\cos x$ and $y=1-\frac{2 x}{\pi}$ that $\cos x>1-\frac{2 x}{\pi}$