Respuesta :

Answer:

f(x) = x² + ax + 1

f'(x) = 2x + a

f'(1) = 2 + a ≥ 0---->a ≥ -2

f'(2) = 4 + a ≥ 0---->a ≥ -4

So if a ≥ -2, then f(x) = x² - 2x + 1 is increasing on [1, 2].