Question

решите уравнение 2cosx=√8/2

Answer 1

$2cosx= frac{ sqrt{8} }{2}$

$2cosx= frac{2 sqrt{2} }{2}$

$2cosx= sqrt{2}$

$cosx= frac{ sqrt{2} }{2}$

x = ± $arccos frac{ sqrt{2} }{2} +2 pi n$, n∈Z

x = ± $frac{ pi }{4}+2 pi n,$ n∈Z