A solid is formed by adjoining two hemispheres to the ends of a right circular cylinder. The total volume of the solid is 14 cubic centimeters. Find the radius of the cylinder that produces the minimum surface area.

Respuesta :

The radius of the cylinder that produces the minimum surface area is 1.34cm and this can be determined by using the formula area and volume of cylinder and hemisphere.

A solid is formed by adjoining two hemispheres to the ends of a right circular cylinder.

The total volume of the solid is 10 cubic centimeters.

The volume of a cylinder is given by:

V = πr²h

The total volume of the two hemispheres is given by:

V = 2 x 2/3 πr³

Now, the total volume of the solid is given by:

V total = πr²h + 2 x 2/3πr³

Now, substitute the value of the total volume in the above expression and then solve for h.

10 =  πr²h + 4/3πr³

h = 10/πr² + 4r/3

Now, the surface area of the curved surface is given by:

A = 2πrh

Now, the surface area of the two hemispheres is given by:

A' = 2 x 2πr²

A' = 4πr²

Now, the total area is given by:

A total = 2πrh + 4πr²

Now, substitute the value of 'h' in the above expression.

A total = 2πr(h = 10/πr² + 4r/3) + 4πr²

Simplify the above expression.

dA = -20/r + 4πr²/3

Now, differentiate the total area with respect to 'r'.

dA/dr =  20/r + 8πr/3

Now, equate the above expression to zero.

0 = -20/r² + 8πr/3

Simplify the above expression in order to determine the value of 'r'.

8πr³ = 60

r = 1.34 cm

Therefore, the radius of the cylinder that produces the minimum surface area is 1.34cm

To learn more about area of a region refer here

brainly.com/question/11952845

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