If a function $f$ is continuous at every point $a$ in an interval $I$, we'll say that $f$ is continuous on $I$.
The Intermediate Value Theorem talks about the values that a
continuous function has to take:
Theorem:
Suppose $f(x)$ is a continuous function on the interval $[a,b]$ with
$f(a) \ne f(b)$. If $N$ is a number between $f(a)$ and $f(b)$, then
there is a point $c$ between $a$ and $b$ such that $f(c)=N$.
In other words, to go continuously from $f(a)$ to $f(b)$,
you have to pass through $N$ along the way.
In this video we
consider the theorem graphically and ask: What does it do for us?