# Math problem

#### leone

I'm still laughing at the Access Denied. It's one of 'em confidential government stars, ain't it?

#### sketchyrx

##### Sweet Disposition
New problem

The cost of manufacturing x caseloads of ballpoint bens is

600x^2 + 600x/x^2 +1

dollars. How many caseloads should be manufactured to have and average cost of \$25? (Average cost is defined as if c(x) is the cost of producing x units, then c(x)/x is the average cost per unit.)

To get rid of the fraction I multiplied both sides by x^2+1 and my equation became
600x^2+ 600x = 25x^2 +25..... then I combined like terms and set it all equal to zero

=575x^2 +600x-25=0

when I graph this it looks like a 'mostly' straight up and down line to the left of the y-axis. Isn't this a parabola and doesn't is open up downward? You can take away my gold stars now. #### Scythe

##### Pro Member
could you write that equation again, but with brackets? #### sketchyrx

##### Sweet Disposition
Okay I hafta go to skool now. Turn in that assignment..... <_<

##### Veteran Member
Originally posted by sketchyrx@Jan 18 2008, 12:13 AM
New problem

The cost of manufacturing x caseloads of ballpoint bens is

600x^2 + 600x/x^2 +1

dollars. How many caseloads should be manufactured to have and average cost of \$25? (Average cost is defined as if c(x) is the cost of producing x units, then c(x)/x is the average cost per unit.)

To get rid of the fraction I multiplied both sides by x^2+1 and my equation became
600x^2+ 600x = 25x^2 +25..... then I combined like terms and set it all equal to zero

=575x^2 +600x-25=0

when I graph this it looks like a 'mostly' straight up and down line to the left of the y-axis. Isn't this a parabola and doesn't is open up downward? You can take away my gold stars now. Possibly there is no solution depending on how you intend to write the bracket.s

##### Veteran Member
if c(x) = 600x^2 + 600x/(x^2 + 1)

then the only solution that fits is a negative number.

c(x)/x = 25
600x + 600/(x^2 + 1) = 25
24x + 24/(x^2 + 1) = 1
24x^3 + 24x + 24 = x^2 + 1

24x^3 - x^2 + 24x + 23 = 0

#### sketchyrx

##### Sweet Disposition
Thanks everyone. I got full credit for this extra credit assignment. Right now I have an A. I share that with everyone here. #### givemfitz

##### Fukushima hybrid gopher
Originally posted by sketchyrx@Jan 18 2008, 12:13 AM

when I graph this it looks like a 'mostly' straight up and down line to the left of the y-axis. Isn't this a parabola and doesn't is open up downward? You can take away my gold stars now. I had to let it go when you said mostly straight line to the left of the y-axis is a parabola. It could be 1/2 a parabola if there were such a thing. :lol: A parabola is what you should've gotten but not what you were describing to my thinking. :wacko:

So congrats and no credit for me. #### sketchyrx

##### Sweet Disposition
That's why I was confused. I know what a parabola is supposed to look like and which direction is should open up depending on the positive or negative in front of the first term. I probably wasn't looking at it with the correct dimensions in the window. Anyhoo. There could be a half-parabola. How bout the square root function?

#### givemfitz

##### Fukushima hybrid gopher
Yeah.....it's called a curve. :lol: But technically if you were denoting that said curve was exactly half of an existing parabola like you said then yeah.......I guess you could have a halfarabola. #### sketchyrx

##### Sweet Disposition
I'll talk to my super-nerdy yet super-smart math teacher about that. :lol:

#### leone

So who remembers integration? and bussing?

#### Scythe

##### Pro Member
Originally posted by sketchyrx@Feb 3 2008, 11:08 PM
There could be a half-parabola. How bout the square root function?
That's only a halfparabola if you tilt your head #### leone

Originally posted by givemfitz@Feb 12 2008, 10:53 PM
and bussing?
Smart ass. #### givemfitz

##### Fukushima hybrid gopher
Well then be specfic. #### leone

Integration in a math thread? Why, I have no idea what I was thinking! :lol:

#### givemfitz

##### Fukushima hybrid gopher
I have no idea what you're SAYING. #### leone

Shut up! I hate you! *slams door*

#### Magilune

##### Pro Member
Now look what you did! <_<

:lol:

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