Answer
The function $f$ has a relative maximum at $x=b$ and the value of the relative maxima is $f\left( b \right)$.
Work Step by Step
If the graph of any function $f$ is increasing on the interval $\left( a,b \right)$ and is decreasing on the interval $\left( b,c \right)$ with no break on interval $\left( a,c \right)$, then it is concluded that function $f$ has a relative maximum at $x=b$ and we can represent the value of the relative maxima by $f\left( b \right)$.
