- #1

- 9

- 0

Where I got stuck:

350=pi(r)^2*h

h=350/pi(r)^2

SA= 2pi(r)^2+2pi(r)(h)

SA= 2pi(r)^2+2pi(r)(350/pi(r)^2)

=(2(pi(r)^3+350))/(pi(r))

I'm stuck here :S

- Thread starter ahmedb
- Start date

- #1

- 9

- 0

Where I got stuck:

350=pi(r)^2*h

h=350/pi(r)^2

SA= 2pi(r)^2+2pi(r)(h)

SA= 2pi(r)^2+2pi(r)(350/pi(r)^2)

=(2(pi(r)^3+350))/(pi(r))

I'm stuck here :S

- #2

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- #3

chiro

Science Advisor

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One thing you should be aware of is that volume is cubic metres (or centimetres or inches or some other unit of length) so you need to convert the liquid quantity to volume by looking at the density.

As Muphrid pointed out above, you want to look into finding a minimum which has a direct correspondence to the derivative being zero.

- #4

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- #5

chiro

Science Advisor

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If you want things in the right units, this is a critical step.

- #6

Mark44

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Homework problems should be posted in the Homework & Coursework section, not in the math technical section.

I am moving your post.

- #7

HallsofIvy

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One thing you should be aware of is that volume is cubic metres (or centimetres or inches or some other unit of length) so you need to convert the liquid quantity to volume by looking at the density.

As Muphrid pointed out above, you want to look into finding a minimum which has a direct correspondence to the derivative being zero.

No, it isn't. Liquid quantityIf you want things in the right units, this is a critical step.

- #8

chiro

Science Advisor

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Yeah you're right: I was under the impression that it was in another unit. My apologies.

- #9

HallsofIvy

Science Advisor

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Happens to me all the time!

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