Question

cos 7x + cos 3x = 0 , помогите пожалуйста, срочно нужно!)

Answer 1

2Cos5xCos2x = 0
Cos5x = 0
5x = π/2 + πk , k ∈Z
x = π/10 + πk/5, k ∈Z
Cos2x = 0
2x = π/2 + πn , n ∈Z
x = π/4 + πn, n ∈Z