Решить уравнение cos(2x+π/4)=1/2

Question

Решить уравнение cos(2x+π/4)=1/2

Answer 1

cos(2x+π/4)=1/2

1)cos(π/6)=1/2

 2x+π/4=π/6+2kπ, 2x=-π/4+π/6+2kπ=-π/12+2kπ

 x=-π/24+kπ, k∈Z

2)cos(11π/6)=1/2

 2x+π/4=11π/6+2kπ, 2x=-π/4+11π/6+2kπ=19π/12+2kπ

 x=19π/24+kπ, k∈Z