Question

Совсем не могу понять,как решается.Помогите,пожалуйста!

Answer 1

cos (...) = 1/2
(...) = π/3 + 2πn
(...)= -π/3 + 2πk

π(8x–8)/3 = π/3 + 2πn
π(8x–8)/3 = -π/3 + 2πk (·3)

π(8x–8) = π + 6πn
π(8x–8) = -π + 6πk (:π)

(8x–8) = 1 + 6n
(8x–8) = -1 + 6k (:8)

x–1 = 1/8 + 6n/8
x–1 = -1/8 + 6k /8

x = 9/8 + 3/4n
x = 7/8 + 3/4k

x = 1,125 + 0,75n , n€Z
x = 0,875 + 0,75k , k€Z