Question

Решите уравнение: 2cos x+1=0

Answer 1

2cos x + 1 = 0

cos x = -0.5

x = ±2π/3 + 2πn, n ∈ Z

Answer 2

$2cos x+1=0$

$2cos x=-1$

$cos x=- frac{1}{2}$

$x=бarccos(- frac{1}{2} )+2 pi n, n$ ∈ $Z$

$x=б( pi -arccos frac{1}{2} )+2 pi n, n$ ∈ $Z$

$x=б( pi - frac{ pi }{3} )+2 pi n, n$ ∈ $Z$

$x=бfrac{ 2pi }{3} +2 pi n, n$ ∈ $Z$