19.3. Найдите значение выражения: 1) 5tg0 + 2sin(-π/6) - 3ctg(-π/4) + 4cos(-π/2); 2) tg(-π/3)ctg(-π/6) + 2cos(-π) + 4sin²(-π/3).

1) 5tg0 + 2sin(-π/6) - 3ctg(-π/4) + 4cos(-π/2) = 5 * 0 + 2 * (-1/2) - 3 * (-1) + 4 * 0 = 0 - 1 + 3 + 0 = **2** 2) tg(-π/3)ctg(-π/6) + 2cos(-π) + 4sin²(-π/3) = -√3 * (-√3) + 2 * (-1) + 4 * (√3/2)² = 3 - 2 + 4 * (3/4) = 3 - 2 + 3 = **4**