SOLUTION: hI1 please help me with this. I have done so many questions before but this one just doesnt give the right answer?? any help would be apreciated The volume of a library is

Question 117465: hI1
please help me with this. I have done so many questions before but this one just doesnt give the right answer?? any help would be apreciated

The volume of a library is 20000 m (cubed) We have to minimize the Surface area to ignore the heat loss.Dtermine the dimensions of the building that will best give us teh minimum Surface area.??
thanks for any help coming this way.
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
For a cylindrical room, h is height, r is the radius.
Volume of the cylinder
Surface area of top and bottom plus unrolled side

You can rearrange the equation to solve for h as a function of r.

Then substitute that back into the surface area equation,

Plot S using various values of r and look for a minimum.
8.1, 5350.
9.1, 4915.
10.1, 4601.
11.1, 4377.
12.1, 4225.
13.1, 4131.
14.1, 4085.
15.1, 4080.
16.1, 4112.
17.1, 4175.
18.1, 4267.
19.1, 4385.
20.1, 4527.
Looks like a minimum at r=15.1.
Now that you have r, go back to your equation for h and solve.

Make sure to check your answer.

Close enough.
r=15.1 m, h=27.9 m
RELATED QUESTIONS
Any four people on a committee of seven people can make a decision for the committee.... (answered by stanbon)

HI1 please help me with this problem . I am done with all my other homework except this... (answered by edjones)

I am not exactly sure if this is a linear equation but I need help!!! I am... (answered by solver91311)

Can you please help me with this question. The problem is 5^x-2=4^x-1. The answer I... (answered by Fombitz)

I have done simple linear equations, such as 5x + 4 = 34, minus the 4 and divide the 30... (answered by stanbon)

im nt sure how to answer this question its: solve abs(-3x+7)=9 i did 7-9=2, so -3x=2... (answered by jim_thompson5910,oberobic)

My Teacher has been of for ages and came in the other day to give us a homework sheet but (answered by nerdybill,richwmiller,solver91311)

Please help me with this: Write an equation for a function that has the shape of... (answered by jim_thompson5910)

. A student is taking a 5 question True-False quiz but he has not been doing any work in (answered by Theo,jsmallt9)