б) 3 sin π/6 + 2 cos π + ctg² π/6

sin π/6 = 1/2, cos π = -1, ctg² π/6 = (cos π/6 / sin π/6)² = (sqrt(3)/3)² = 1/3. Ответ: 3/2 + 2*(-1) + 1/3 = -1/6.