1) 2cosx+√2=0 2) cosP/6s=√3/2 3) 2cos1/4x-1=0

Найдем корни уравнений.

1) 2 * cos x + √2 = 0;

2 * cos x = - √2;

cos x = - √2/2;

x = + -arccos (-√2/2) + 2 * п * n, n ∈ Z;

x = + -3 * п/4 + 2 * п * n, n ∈ Z;

2) cos (P/6 * s) = √3/2;

(p/6 * s) = + -arccos (√3/2) + 2 * п * n, n ∈ Z;

(p/6 * s) = + -п/3 + 2 * п * n, n ∈ Z;

Умножим на 6.

(p * s) = + -п/3 * 6 + 6 * 2 * п * n, n ∈ Z;

(p * s) = + -2 * п + 12 * п * n, n ∈ Z;

s = + -2 * п/п + 12 * п/п * n, n ∈ Z;

s = + -2 + 12 * n, n ∈ Z;

3) 2 * cos (1/4 * x) - 1 = 0;

2 * cos (1/4 * x) = 1;

cos (1/4 * x) = ½;

¼ * x = + -arccos (1/2) + 2 * п * n, n ∈ Z;

¼ * x = + -п/3 + 2 * п * n, n ∈ Z;

x = + -4 * п/3 + 4 * 2 * п * n, n ∈ Z;

x = + -4 * п/3 + 8 * п * n, n ∈ Z.