Question

помогите пж у меня кр cos4xcosx-sin4xsinx=-1/2

Answer 1

Решение
cos4xcosx-sin4xsinx=-1/2
сos(4x + x) = - 1/2
cos5x = - 1/2
5x = (+-) arccos(-1/2) + 2πk, k ∈ Z
5x = (+-) (2π/3) + 2πk, k ∈ Z
x =  (+-) (2π/15) + 2π/5, k ∈ Z