Think Bolzano

Calculus Level 1

Fill in the blank.

Let \(f(x)\) be a continuous real-valued function with \(f(1) = -1\) and \(f(4) = 3.\) If \(1 < c < 4,\) then each of the following except for \(\text{______}\) is guaranteed to be a value of \(f(c).\)