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Nimble · 02-20-2008, 04:54 PM,

I've got a problem with maths:

I missed a lesson, therefor i didn't get what the vertical lines in a function mean. I've looked in my textbook but it wasn't explained clearly.
For instance: f(x)=|x-6|

pchwang · 02-20-2008, 04:58 PM,

Nimblewright, the vertical lines indicate absolute value. That means that any number between the lines is it's absolute counting value.

For instance |6| = 6 and |- 6| = 6.

A function with absolute value marks should appear like a "V" on your graph.

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Nimble · 02-20-2008, 05:18 PM,

thank you, it has been a great help

Dopamino · (This post was last modified: 02-28-2008, 01:43 AM by Dopamino.)

Ok, I've got a problem

How do you do this?

The problem - g(f(x)) where g(x)=x^(3/4) and f(x)=4x^-5

I get the concept for the most part, but my answer keeps on coming out wrong. The correct answer according to my book is 2^(3/2)x^(-15/4)

I need to see detailed work with explanations please. I need to find out what I'm doing wrong.

Thanks:)

Edit - nvm, got it off yahoo answers.

Here's how to do it if anyone is interested:

g[f(x)]
[4 x^(-5)]^(3/4)
0= 4^(3/4) [x^(-5)]^(3/4)]
0= (2?)^(3/4) x^[(-5) . (3/4)]
0= 2^[2 . (3/4)] x^[(-5) . (3/4)]
0= 2^(3/2)] x^(-15/4)

2^(3/2)] x^(-15/4)

I mostly lurk around Media Center these days.

Heartless · (This post was last modified: 05-04-2008, 06:08 PM by Heartless.)

hello

so right now I need some math help. We're reviewing for final exams and I need help with 2 more problems on this sheet. They're related to logs and exponents. You DO NOT have to tell me the answers, just guide me as to what to do.

Ok, 1st one.

Daniel's Print Shop purchased a new printer for $35,000. Each year it depreciates (loses value) at a rate of 5%. What will its approximate value be at the end of the fourth year?
a) $33,250.00
b) $30, 008.13
c) $28,507.72
d) $27,082.33
This is what I did: (The formula is y=a(b)^x)
y=x
a=35,000
b=.05 -> (5%)
x=4
So I put this together, x=35000(.05)^4, but I got 2187.5
So there's my problem with that one, not sure what to do, help is really appreciated.

2nd one

On January 1, 1999, the price of gasoline was $1.39 per gallon. If the price of gasoline increased by 0.5% per month, what wsa the cost of one gallon of gasoline, to the nearest cent, on january 1 one year later?
-I really don't know in this one, would the ^x be 4, or 5? It would be I guess x=1.39(0.5)^4, right?

SwissScorch --> Heartless

05-04-2008, 06:16 PM,

' Wrote:So I put this together, x=35000(.05)^4, but I got 2187.5

On January 1, 1999, the price of gasoline was $1.39 per gallon. If the price of gasoline increased by 0.5% per month, what wsa the cost of one gallon of gasoline, to the nearest cent, on january 1 one year later?
-I really don't know in this one, would the ^x be 4, or 5? It would be I guess x=1.39(0.5)^4, right?

first one: Should be 35000(.95)^4 = 28507.719
second one: 1.39(1.005)^12 = $1.48

Those may not be right, I haven't done stuff like that in a looooong time.

Edit: Just plugged them in and got the answers, they look pretty reasonable to me.

Heartless · 05-04-2008, 06:22 PM,

yup, you subtract the decimal percent from 100, I had completely forgotten about that. .95 makes the 1st answer equal to b). And for the 2nd one I got $1.46, which looks right. So thanks alot, this really did save me some time.

SwissScorch --> Heartless

Boss · 05-05-2008, 07:26 PM,

Sorry, folks, this isn't math, but I have a problem with my HTML. I'm trying to get the bloody frames working. Code attached.

Code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"

&nbsp;&nbsp;&nbsp;&nbsp;"http://www.w3.ord/TR/html4/loose.dtd">

<!--CS-125H-30 Page Layout with Frames

&nbsp;&nbsp;&nbsp;&nbsp; Author:&nbsp;&nbsp;Aaron Porter

&nbsp;&nbsp;&nbsp;&nbsp; Date:&nbsp;&nbsp;5 May 2008

-->

<html lang="en-US">

<body>

<title>

Freelancer/Discovery Datasite

</title>

<frameset rows="15%,*" framespacing="10" scrolling="no">

<frame name="logo" noresize scrolling="no" src="discologo.html" />

</frameset> 

<frameset cols="25%,*" framespacing="10" scrolling="auto">

<frame src="linkframe.html" name="links" noresize scrolling="no" />

<frame src="main.html" name="main" noresize scrolling="yes" />

</frameset>

</body>

</html>

In theory, at least, this should make a page with three frames, a row along the top with the Disco logo, a column to the left with links, and a main window in the bottom right.

EDIT:

Killed the body tags. Now I have a page with the disco logo, a list of links, and a "page not found". That last is my fault, haven't made it yet;)

Oh, I also found that adding a second "</frameset>" is a bad idea.

EDIT2:

Final code of the page, please be sure to drop by and see it:

Code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN" "http://www.w3.org/TR/html4/frameset.dtd">

<!--CS-125H-30 Page Layout with Frames

&nbsp;&nbsp;&nbsp;&nbsp; Author:&nbsp;&nbsp;Aaron Porter

&nbsp;&nbsp;&nbsp;&nbsp; Date:&nbsp;&nbsp;5 May 2008

-->

<! I set the document type and open the HTML>

<html lang="en-US">

<! Set the title>

<title>

Freelancer/Discovery Datasite

</title>

<frameset rows="25%,*" framespacing="10" scrolling="no">

<frame name="logo" noresize scrolling="no" src="discologo.html" />

<frameset cols="10%,*" scrolling="auto">

<frame src="linkframe.html" name="links" noresize scrolling="no" />

<frame src="main.html" name="main" noresize scrolling="yes" />

</frameset>

<! I close the HTML coding and body and save the file>

</html>

Zealot Wrote:Just go play the game and have fun dammit.

Treewyrm Wrote:all in all the conclusion is that disco doesn't need antagonist factions, it doesn't need phantoms, it doesn't need nomads, it doesn't need coalition and it doesn't need many other things, no AIs, the game is hijacked by morons to confuse the game with their dickwaving generic competition games mixed up with troll-of-the-day.

Heartless · 05-11-2008, 08:02 PM,

Hi, more math help plez!:)

I think I'm doing better on these practice regents. But I need help with one thing.

3cos2θ+sinθ-1=0

So to me the sinθ doesn't seem like it's enough, would it be just 1?

SwissScorch --> Heartless

Nevermore · (This post was last modified: 05-11-2008, 11:10 PM by Nevermore.)

Oh, you got a hard nut there:P

Anyway, that's my solution. Basic idea: Use a sum formula for cosinus, use the identity sin^2 + cos^2 = 1, substitute sin(x), solve the resulting quadratic equation and resubstitute.

First off, I don't like to type Theta all the time, so I just use x.

That would make:

3cos(2x) + sin(x)-1 = 0 <=>

3cos(x+x) + sin(x) = 1 <=>

3(cos^2(x)-sin^2(x)) + sin(x) = 1 <=> //Used the sum formula

3((1-sin^2(x))-sin^2(x)) + sin(x) = 1 <=> //Identity cos^2 = 1-sin^2(x)

3 - 6sin^2(x) + sin(x) = 1 <=>

sin^2(x) - (1/6)sin(x) = 1/3 <=>

u^2 - (1/6)u = 1/3 with substitution u=sin(x) <=>

(u - (1/12))^2 = 49/144 <=> //quadratic complement

|u - (1/12)| = 7/12 <=>

u1 = -1/2, u2 = 2/3

Resubstitution:

u1 = sin(x1) <=> x1 = arcsin(-1/2) = pi/6
u2 = sin(x2) <=> x2 = arcsin(2/3) = 0,7297276562...

Edit: Ah, I forget the other solutions... So, everything in the form of 2pi*k + x1 or 2pi*k + x2 are solutions, with k being an integer.

But the Raven, sitting lonely on that placid bust, spoke only
That one word, as if his soul in that one word he did outpour.
Nothing further then he uttered; not a feather then he fluttered--
Till I scarcely more than muttered, "Other friends have flown before--
On the morrow he will leave me, as my Hopes have flown before."
<blockquote>Then the bird said, "Nevermore."</blockquote>
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</div>

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