# Definition

Suppose that $f$ satisfies the conditions of the mean value theorem on $[a,b]$, then there is a point $c \in \left( {a,b} \right)$ such that the tangent at $\left( {c,f(c)} \right)$ is parallel to the secant determined by $\left( {a,f(a)} \right)\,\& \,\left( {b,f(b)} \right)$.