Решите уравнение Cos x*cos п/3 - sin x*sin п/3=1/√2
Сos(x+π/3)=1/√2 x+π/3=-π/4+2πn,n∈z U x+π/3=π/4+2πk,k∈z x=-7π/12+2πn,n∈z U x=-π/12+2πk,k∈z