Figure8b
Supposea function is continuousand non-negativeon the interval and supposethat is the
regionbetweenthe curve and the -axis(Figure8a). If this regionis revolvedaboutthe -axis,it will
generatea solid that will havecircularcross-sections(Figure8b) with radii of at each Eachcross-
sectionalarea can be calculatedby
Sincethe volumeis definedas
the volumeof the solid is