It is proved that the equation x ^ 5-3x-1 = 0 has at least one root

It is proved that the equation x ^ 5-3x-1 = 0 has at least one root

prove:
Let's briefly introduce the zero point theorem
If the function f (x) is continuous in the interval [a, b], and f (a) * f (b) 0
And there is another small segment below the x-axis, f (x)