2cox+1=0;
2cosx= -1;
cosx= - 1/2;
x= ±arccos(- 1/2)+2πn, n ∈ Z;
x= ± (π - arccos 1/2)+2πn, n ∈ Z;
x= ±(π - π/3)+2πn, n ∈ Z;
x= ± 2π/3 +2πn, n ∈ Z.
ответ: ± 2π/3 +2πn, n ∈ Z.
2cox+1=0;
2cosx= -1;
cosx= - 1/2;
x= ±arccos(- 1/2)+2πn, n ∈ Z;
x= ± (π - arccos 1/2)+2πn, n ∈ Z;
x= ±(π - π/3)+2πn, n ∈ Z;
x= ± 2π/3 +2πn, n ∈ Z.
ответ: ± 2π/3 +2πn, n ∈ Z.