from the values calculated, as below, from the original equation.

${\displaystyle x}$	${\displaystyle -1}$	${\displaystyle 0}$	${\displaystyle 1}$	${\displaystyle 2}$	${\displaystyle 3}$	${\displaystyle 4}$	${\displaystyle 5}$	${\displaystyle 6}$
${\displaystyle y}$	${\displaystyle -4{\tfrac {1}{3}}}$	${\displaystyle 1}$	${\displaystyle 2{\tfrac {1}{3}}}$	${\displaystyle 1{\tfrac {2}{3}}}$	${\displaystyle 1}$	${\displaystyle 2{\tfrac {1}{3}}}$	${\displaystyle 7{\tfrac {2}{3}}}$	${\displaystyle 19}$

A further exercise in maxima and minima is afforded by the following example:

The equation to a circle of radius ${\displaystyle r}$, having its centre ${\displaystyle C}$ at the point whose coordinates are ${\displaystyle x=a}$, ${\displaystyle y=b}$, as depicted in Fig. 29, is:

This may be transformed into

Now we know beforehand, by mere inspection of the figure, that when ${\displaystyle x=a}$, ${\displaystyle y}$ will be either at its maximum value, ${\displaystyle b+r}$, or else at its minimum value, ${\displaystyle b-r}$. But let us not take advantage of this