The total surface area of the cylinder is s=2πr2+2πrh Volume of the cylinder is given by V=πr2h Put the value of h in the expression of surface area. s=2πr2+2πr(
V
πr2
)
ds
dr
=4πr−
2V
r
For surface area to be maximum and minimum
ds
dr
=0 V=2πr3 Put thte value in the expression of height. h=