Réponse :
f(x) = a x³ + b x + c
* f(0) = 3 = c
* f '(x) = 3 a x² + b ; f '(1) = 0 = 3 a + b
* f '(2) = 12 = 12 a + b
3 a + b = 0 ⇔ b = - 3 a
12 a + b = 12 ⇔ 12 a - 3 a = 12 ⇔ 9 a = 12 ⇔ a = 4/3
b = - 3* 4/3 = - 4
f(x) = 4/3) x³ - 4 x + 3
Explications étape par étape :
