Показательные уравнения и неравенства, тригонометрическое уравнение

1. 3^х-3^ (х+1) ≤о

2. (1/6) ^ (х+1) = 36^ (х-1)

3. 4 cos²x-1=0

3^x (1 - 3) ≤ 0

3^x ≥ 0

x - любое

2) 6^ (-x - 1) = 6^ (2x - 2)

-x - 1 = 2x - 2

3x = 1

x = 1/3

3) 4 Сos²x = 1

Cos²x = 1/4

a) Cos x = 1/2

x = = - arcCos 1/2 + 2πk, k ∈Z

x = + - π/3 + 2πk, k ∈Z

б) Cos x = - 1/2

x = + - arcCos (-1/2) + 2πn, n ∈Z

x = + - 2π/3 + 2πn, n ∈Z