Решите уравнения cos x = -1:2 cos x = -1 2cos x-1=0 √2cos x - 1=0

Question

Решите уравнения
cos x = -1:2
cos x = -1
2cos x-1=0
√2cos x - 1=0

Answer 1

Cosx=-1/2      x=+-(π-π/3)+2πk =+-2π/3+2πk   k∈Z
cosx=-1    x=π+2πk  k∈Z
2cosx=1   cosx=1/2   x=+-π/3+2πk  k∈Z
cosx=1/√2=√2/2   x=+-π/4+2πk   k∈Z