Question

A cylindrical can has a volume of 16 cm 3. What dimensions yield the minimum surface​ area? 1. The radius of the can with the minimum surface area is ______ cm. (Simplify your answer.) 2. The height of the can with the minimum surface area is ______ cm. (Simplify your answer.)

Answer 1

Answer:

radius = 1.37 cm

height = 2.71 cm

Step-by-step explanation:

We are given volume = 16 m³.

Formula for volume of a cylinder is;

V = πr²h

Thus,

πr²h = 16

h = 16/πr²

Now formula for the surface area is;

S = 2πr² + 2πrh

Putting 16/πr² for h gives;

S = 2πr² + 2πr(16/πr²)

S = 2πr² + 2π(16/πr)

S = 2π(r² + 16/πr)

To minimize, we will find the derivative of S and equate to zero

S' = 2π(2r - 16/πr²) = 0

4πr - 32/r² = 0

4πr = 32/r²

r³ = 32/4π

r = ∛(32/4π)

r = 1.37 cm

From h = 16/πr²;

h = 16/(π × 1.37²)

h = 2.71 cm