QQ - Geometrical Applications of Calculus! (1 Viewer)

[Smile12345]

Hello All...

Could someone please help me with the following question?

"The formula for the surface area of a cylinder is given by ,where r is the radius of its base and h its height.

Show that if the cylinder holds a volume of , the surface area is given by the equation

Hence find the radius that gives the minimum surface area."

Thanks in advance.

 

[Smile12345]

BTW - How do I get Pi in latex?

 

[Kurosaki]

\pi

 

[QZP]

V: pi.r^2.h = 54pi

Rearrange for h and then sub h into S = 2pi.r(r+h)

 

[Smile12345]

V: pi.r^2.h = 54pi

Rearrange for h and then sub h into S = 2pi.r(r+h)

Which comes too:

 

[Smile12345]

\pi

Thanks!

 

[enigma_1]

The answer's probably wrong but the process should be right. I was focused on trying to squish it all on one page lol soz

 

[anomalousdecay]

The answer's probably wrong but the process should be right. I was focused on trying to squish it all on one page lol soz

You should get r=3m.

So you are right.