It is proved that equation 1 + X + (x ^ 2) / 2 + (x ^ 3) / 6 = 0 has only one real root In a hurry We should use the relevant methods of the mean value theorem to solve the problem

It is proved that equation 1 + X + (x ^ 2) / 2 + (x ^ 3) / 6 = 0 has only one real root In a hurry We should use the relevant methods of the mean value theorem to solve the problem

First, use the zero point theorem to prove the existence, such as f (0) f (- 2) 0, so the root is unique!