Cos²x + 8Sinx -8 = 0
1 - Sin²x + 8Sinx -8 = 0
-Sin²x +8Sinx -7 = 0
Sin²x -8Sinx +7 = 0
Sinx = 1 Sinx = 7
x = π/2 + 2πk , k ∈ Z ∅
Смотри.......................