Question

Вычислите предел функции. Пожалуйста

Answer 1

Решение lim x--> 4 [(2x² - 5x - 12) / (x² + x - 20)] ; 1) 2x² - 5x - 12 = 0 D = 25 + 4*2*12 = 121 x₁ = (5 - 11)/4 x₁ = - 1,5 x₂ = (5 + 11)/4 x₂= 4 2x² - 5x - 12 = 2*(x + 1,5)*(x - 4) 2) x² + x - 20 = 0 x₁ = - 5 x₂ = 4 x² + x - 20 = (x + 5)*(x - 4) = lim x--> 4 [2*(x + 1,5)*(x - 4)] / [(x + 5)*(x - 4)] = = lim x--> 4 (2x + 3) / (x + 5) = (2*4 + 3)/(4 + 5) = 11/9 = 1 (2/9)