It is proved that the equation x ^ 3-3x + 1 = 0 can not have two different roots on the interval [0,1]?

It is proved that the equation x ^ 3-3x + 1 = 0 can not have two different roots on the interval [0,1]?

Let f (x) = x ^ 3-3x + 1
f'(x)=3x^2-3
Let f '(x) = 0
x=1 x=-1
F (x) is a simple increasing function on the interval [- 1,1]
There can be at most one intersection with the X axis