Mathematics

Problem

Region

R

is bounded above by

y=x^{2}

and below by

y=0

for

0\le x\le 2

. When

R

is revolved about the horizontal line

y=-1

, a solid of revolution is generated. For a representative vertical slice at

x

, which of the following is the radius of the corresponding disc? a)

|x^{2}-1|

x^{2}+1

x^{2}

x^{2}-1