This is the standardformulafor the volumeof the sphere.
The Methodof Washers
To generalizeour results,if f and g are non-negativeand continuousfunctionsand
for
Thenlet be the regionenclosedby the two graphsand boundedby and Whenthis region
is revolvedaboutthe -axis,it will generatewasher-likecross-sections(Figures10a and 10b).In this case,
we will havetwo radii:an innerradius and an outerradius The volumecan be givenby: