Question

how do i find area of cylinder whose radius is increasing from r to R

Answer 1

Formula is 2pierh +2pier^2

Where r is radius of the cylinder , h is the height
If R>r, then,

( 2 pie Rh+ 2 pie R^2) - ( 2 pie rh + 2 pie r^2)

Therefore answer is (2 pie Rh+ 2 pie R^2) - ( 2 pie rh + 2 pie r^2)