Question

Помогите Б) , быстро

Answer 1

$g(x)=3-cos2x\\\\\\g\Big(\dfrac{\pi}{2}\Big)=3-cos\pi =1-(-1)=4\\\\\\g\Big(\dfrac{\pi}{4}\Big)=3-cos\dfrac{\pi}{2}=3-0=3\\\\\\g\Big(-\dfrac{\pi}{4}\Big)=3-cos\Big(-\dfrac{\pi}{2}\Big)=3-0=3$