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MunkyButt
06-24-2004, 09:00 PM
i can help if you have questions.

Diamond187
06-24-2004, 09:22 PM
Alright, here's something interesting for you to work out:

xln(x)=x

Gimme all possible solutions, then we will all collectively call you a basic algebra whiz.

caprarioreed25
06-24-2004, 10:42 PM
There are no possible solutions?

Diamond187
06-25-2004, 01:28 AM
Nope, it is solvable. It really isn't that hard either. But there's one trick answer which might get some people.

Danielle
06-25-2004, 08:30 AM
Darn. You had to use natural log rythm. The one thing that I only moderately understand from Alg II. Eh, I will work the problem tonight.

Diamond187
06-25-2004, 02:35 PM
As a big hint I'll say that you should logically come up with 2 answers, and then rule one of them out.

The First
06-26-2004, 04:33 AM
I'm not getting the question... is it x*ln(x) = x? Or does xln(x) have a different meaning?

Yes, I know. Stupid german with his different way of writing mathematical terms >_<

Afterburner
06-26-2004, 05:31 AM
I'm guessing that either:

Ln(x) = 1
or
x = 0

If ln(x) = 1 then x = e

If x = 0 then ln(x) is undefined, so it's out anyways.

Am I right? x = e?

Try this, another easy one: derive the quadratic formula.

Diamond187
06-28-2004, 04:09 PM
Yep, AB is right again.

And I did that once in my chemistry course. It's kinda cool when you figure out how to do it, but it really, really makes you wonder how they came up with a cubic formula.

caprarioreed25
06-28-2004, 09:10 PM
Try this, another easy one: derive the quadratic formula.

x = -b ± the square root of b² - 4ac all over 2a

I could've solved the natural logarithm problem at one time, but I've forgotten that stuff. It was too boring for me...

eatmorchikin6464
06-28-2004, 09:27 PM
Im not going to derive the quadratic formula, that takes lines and lines and lines.

Diamond187
06-28-2004, 09:53 PM
He said derive, not state.

And yeah, it might be hard to do in computer math, and confusing to read.

Vagrant
06-28-2004, 10:32 PM
Wait... looking at the natural log function...

ln(x^x * x) would be simplified. And now I'm officially confused as to how AB got that answer.

Diamond187
06-28-2004, 10:42 PM
Woah, I've got no idea how you got that. I think you might be confused about some of the notation or something. The equation is, in words:

x times the natural log of x equals x

I hope that clears up something of your misunderstanding.

Vagrant
06-28-2004, 10:53 PM
I might be misunderstanding this. I'm treating it like a log function, where the equals is the power to which the log is multiplied.

Or, I screwed my orders.

Simplified, is it: ln(x^2x) ?

Diamond187
06-28-2004, 10:57 PM
OK, I see how you get the x^x part inside the log but where the 2 comes from I don't see. And exactly what would that be equal to when you simplify the left side to ln(x^2x)?

The First
06-28-2004, 11:05 PM
T'woud be ln(x^x) = x
Which would be e^x = x^x, would it not?
Which means x = e. At least that's following Vagrants line of thought. The only way I get a second answer is the way Afterburner did.

And exactly how do you want someone to derive the Quadratic Formula? It has three variables (if you mean the entire -b +- The root of... blah blah blah). If you mean f(x)=ax²+bx+c, the derivative is 2ax+b

Diamond187
06-28-2004, 11:15 PM
lol

He means derive the -b +- blah blah.

And it doesn't have 3 variables. It has 1 variable and 3 constants. Set up a generic polynomial and you'll see.

ax^2+bx+c=0

a,b&c are all constants. x is your only variable.

The First
06-29-2004, 04:56 AM
Silly german understood something completely different under deriving. Apparently. I think. Anyways, I googled, it, I get what he meant. Yay for commas!

Vagrant
06-29-2004, 07:42 AM
Bleh, sorry, having trouble remembering.

ln(x^x) = x

Log base e (x^x) = x

Now my memory completely died here, and I completely forgot what to do.

Diamond187
06-29-2004, 09:04 AM
You need to anti-log both sides to get rid of the ln.

Vagrant
06-29-2004, 05:26 PM
Err, nevermind. I got it now. I remember.

E^x = X^x

E=X

I was having problems 'cuz I'm not used to doing natural log functions. I'm used to doing normal log functions. I forgot the power rule and the number across the equal sign thingy.

Vince
06-30-2004, 06:44 PM
or you can just make x=0 that leaves it 0=0
HA! I WIN! :p

Afterburner
06-30-2004, 07:40 PM
...

This was discussed earlier......ln (0) is undefined.

Diamond187
07-01-2004, 02:31 AM
Well, theretically, ln(0) is -infinite, and does -infinite*0=0? Iunno, if you can prove it does, you belong at NASA.

The First
07-01-2004, 07:22 AM
Isn't it defined that anything multiplied with 0 will equal 0? Be it a real or imaginary number? I can't say I've spent any time at all thinking about the mathematical properties of infinity, but if you take infinity zero times, then you never took infinite... but I'm going to go off on a limb here and assume that it isn't that simple.

Vince
07-01-2004, 10:33 AM
then i dunno *shrug* i tryed

Diamond187
07-01-2004, 12:08 PM
infinite*0 isn't that simple, and if you think about it, it does make sense. We all know that 0/0 is completely unusable stated like that, well, we can expand that form to something like this 0*(1/0) and obviously 1/0=infinite, so

infinte*0=0/0