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September 6th, 2015, 12:52 AM   #1
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Maths homework

Hi,
I can't get my head around this problem. Any help is appreciated.
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Last edited by skipjack; September 6th, 2015 at 01:11 AM.
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September 6th, 2015, 01:08 AM   #2
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It's easy. I will give you hints.
First one tells the cost for given amount.
Second one, try to remember $\displaystyle f'$ is the rate of change.
I hope you find it.

Last edited by skipjack; September 6th, 2015 at 01:13 AM.
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September 6th, 2015, 01:17 AM   #3
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Presumably, $f'\!(v)$ denotes the rate of change of $f(v)\!$ with respect to $v$.
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September 6th, 2015, 01:24 AM   #4
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Quote:
Originally Posted by skipjack View Post
Presumably, $f'\!(v)$ denotes the rate of change of $f(v)\!$ with respect to $v$.
I am not sure, but I feel it represents rate of change of cost when the amount is at 200 l

Last edited by skipjack; September 6th, 2015 at 08:25 AM.
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September 6th, 2015, 01:34 AM   #5
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a) would be for 200 litres cost 4200$?
b) I'm not getting the rates of change idea

Last edited by skipjack; September 6th, 2015 at 08:28 AM.
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September 6th, 2015, 04:09 AM   #6
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Quote:
Originally Posted by skitdemon View Post
a) would be for 200 litres cost 4200$?
Yep.

Quote:
b) I'm not getting the rates of change idea
When you produce more and more chemical, the unit cost of the chemical will increase. f'(200) = 0.05 means that the cost increases at a rate of 0.05 when you are at your 200th litre of chemical.

If you plot the function on a graph, and draw a tangent at the point where x = 200, the slope of the tangent will be 0.05, which shows how fast the cost is increasing at that exact point.

Last edited by skipjack; September 6th, 2015 at 08:28 AM.
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September 6th, 2015, 04:20 AM   #7
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Originally Posted by 123qwerty View Post
Yep.


When you produce more and more chemical, the unit cost of the chemical will increase. f'(200) = 0.05 means that the cost increases at a rate of 0.05 when you are at your 200th litre of chemical.

If you plot the function on a graph, and draw a tangent at the point where x = 200, the slope of the tangent will be 0.05, which shows how fast the cost is increasing at that exact point.
That's what I was saying.

Last edited by skipjack; September 6th, 2015 at 08:27 AM.
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September 6th, 2015, 08:17 AM   #8
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I get it now, thanks!
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