Question

Can anyone help me in finding the min/max with this online graphing calculator?

http://my.hrw.com/math06_07/nsmedia/tools/Graph_Calculator/graphCalc.html

Answer 1

What is the function you're trying to graph?

Answer 2

Use wolfram alpha for graphing... http://www.wolframalpha.com/

Answer 3

f(x) +-.000006x^4 + .0017x^3 +.03x^ -24x+110, I am having trouble finding the min/max

Answer 4

I can just tell you what the min and max is...lol

Answer 5

wait, why is there a +- at the beginning of f(x)?

Answer 6

which one is it?

Answer 7

Oops supposed to be a negative

Answer 8

LOL...you can tell the answer, I won't tell

Answer 9

I went to that online calculator and it gives A LOT of information
The question is as follows, I am not good with word problems.

Answer 10

I can find it but it will take a while...remember you can also take the double prime of the function...

Answer 11

If it doesn't have a domain, then there is no min or max

Answer 12

The avg. cost (in dollars) per item of manufacturing x thousand cans of spray paint is given by:

-.000006x^4 + .0017x^3 +.03x^ -24x+1110

How many cans should be manufactured if the average cost is to be as low as possible? What is the average coast in that case?

Answer 13

There was no domain given

Answer 14

well, we can eliminate anything less than zero, so the domain is x > 0

Answer 15

Double prime...you lost me there

Answer 16

matter of fact...the domain is x >= 1

Answer 17

f''(x)

Answer 18

Right

Answer 19

The minimum of the function is -988, but I don't know if it applies here because x and y both have to be positive in order for cost and no of cans to make sense

Answer 20

do you mind telling my how you got that

Answer 21

Oh and Thank You!

Answer 22

I used my calc, but trust me, I highly doubt that it applies here...

Answer 23

x and y values must be positive...cost can't be negative and no. of cans can't be negative either...

Answer 24

There is no max....max is infinity

Answer 25

Maybe that is y I am having issues with this one...so since this is a polynomial wouldn't there be more that one min....with the peaks and valleys

Answer 26

Yes, you're right, but, I only see two so far because of the window limit.

Answer 27

Oh ok....TY

Answer 28

Is your teacher trying to torture you on purpose?

Answer 29

You know what....I'm going to take f''(x) myself and find out all the possible min, maxes

Answer 30

f''(x) = 51x/5000 + 18/x^26

Answer 31

Graph that

Answer 32

Yes....pure toture

Answer 33

Don't worry ...we will figure this out...

Answer 34

What is that function you just gave me

Answer 35

that is f"(x)

Answer 36

ok

Answer 37

Okay, I have it....You have to find f'(x) and f''(x). Set f'(x) = 0 and solve for x....don't worry, I will do it for you...

Answer 38

This may take a minute though

Answer 39

You are super duper awesome!

Answer 40

almost done....I found x for f'(x) ......it's 68.5994, now if you plug that into f''(x)....you will get your min or max

Answer 41

looks like f''(x) is positive....so we have a min at f(x) = 0.69

Answer 42

WOW...awesome...working on it now

Answer 43

That must the minimum cost....I'm guessing...if you plug f(.69) into the function, you will get how many cans is produced....

Answer 44

f(.69) back into the original function that is...

Answer 45

wait...I can't plug those #'s in that fast...lol

Answer 46

264.6 or 265 cans

Answer 47

Wow, what a stumper

Answer 48

Your teacher is just wrong for that one...lol

Answer 49

So the minimum cost is .69 cents to produce 265 cans.

Answer 50

LOL...you are hilarious....I am sure he does not care....this was my 2nd to last problem. I was working on this ALL DAY!

Answer 51

I can imagine

Answer 52

Ur a genius, it only too you ten minutes!

Answer 53

Your teacher must have been laughing to himself when he assigned this problem.

Answer 54

I had a little bit of help...online calcs, graphing calcs and wolfram alpha....Without those, I'm like you...taking all day...

Answer 55

But if you know what to do in the general sense, that helps....the key is knowing that you needed f'(x) and f''(x) to help you find the minimum cost

Answer 56

Awesome.....I did not realize that you could attach files as well

Answer 57

:)