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