Question

№568
2,4,6.
ПОМОГИТЕ С Д/З.

Answer 1

$arccos1=0\\\\arccos\frac{1}{2}=\frac{\pi}{3}\\\\arccos(-\frac{\sqrt2}{2})=\pi -arccos\frac{\sqrt2}{2}=\pi-\frac{\pi}{4}=\frac{3\pi}{4}$