Так как косинус четная функция, то cos(π/2-3x)= cos (3x-π/2)Решаем уравнение: cos ( 3x-π/2) = √3/23x - π/2 = ± arccos (√3/2) + 2π·n, n∈ Z3x - π/2 = ± (π/6) + 2π·n, n∈ Z3x = π/2 ± (π/6) + 2π·n, n∈ Zx = π/6 ± (π/12) + (2π/3)·n, n∈ Z иливычитая получим: складывая получим:х₁= π/2 - (π/6) + (2π/3)·n, n∈ Z х₂= π/2 + (π/6) + (2π/3)·n, n∈ Zх₁= π/3 + (2π/3)·n, n∈ Z х₂=2π/3 + (2π/3)·n, n∈ Zпри n =0 получаем корниπ/3 и 2π/3 при n = 1(π/3) + (2π\3) = π и (2π/3) + (2π/3)= 4π/3при n = 2(π/3) + (2π/3)·2=(5π\3) и ( 2π/3) +(2π/3)·2=(6π\3)=2π 3π/2 <(5π/3) <2π3π/2 < 2π≤2πОтвет. На [3π/2; 2π] два корня: (5π.3) и 2π