Hi David,
(x-1)/x = 1/y
1-(1/x) = 1/y
1/x = 1-(1/y)
1/x = (y-1)/y
So the answer is :
x = y / (y-1)
MMmmmh, maths ... so exciting
![[xx(]](./images/smilies/smiley11.gif "Dead")
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| Author: | David Collins [ Sun Jan 25, 2009 12:50 am ] |
| Post subject: | Stupid Algebra Question |
I feel like a fool having to ask, but for some reason I'm going around and around with this one without coming to an answer. x/(x-1) = y How do I solve for x? I'm just hitting some stupid mental block here. |
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| Author: | Christophe Grellier [ Sun Jan 25, 2009 2:14 am ] |
| Post subject: | Re: Stupid Algebra Question |
Hi David, (x-1)/x = 1/y 1-(1/x) = 1/y 1/x = 1-(1/y) 1/x = (y-1)/y So the answer is : x = y / (y-1) MMmmmh, maths ... so exciting
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| Author: | K.O. [ Sun Jan 25, 2009 4:17 am ] |
| Post subject: | Re: Stupid Algebra Question |
For x=10 ,y= 1.11111... For X=100 ,y= 1.0101... For X=1000 ,y= 1.001001... For x=10,000 .y= 1.0001001... So the answer takes the form of a graph. If I remember correctly(it's been a while)? Reminds me of Fractals and chaos theory http://www.fractalwisdom.com/FractalWisdom/fractal.html |
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| Author: | K.O. [ Sun Jan 25, 2009 4:54 am ] |
| Post subject: | Re: Stupid Algebra Question |
Problem is I can't remember if x=1 would make it all wrong... 1/(1-1)=y (can't divide by zero) |
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| Author: | Christophe Grellier [ Sun Jan 25, 2009 5:08 am ] |
| Post subject: | Re: Stupid Algebra Question |
The graph looks like that : |
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| Author: | K.O. [ Sun Jan 25, 2009 5:40 am ] |
| Post subject: | Re: Stupid Algebra Question |
Is that, for all x, such that x~=1 http://en.wikipedia.org/wiki/Division_by_zero#Extended_real_line Set theory? It really has been a long long time since a symbolic logic class caused a little curiosity towards Boolean alg and such. I have mind probs(memory and concentration) I tend to feel my way now... 
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| Author: | David Collins [ Sun Jan 25, 2009 9:21 am ] |
| Post subject: | Re: Stupid Algebra Question |
Thanks Christophe! That's it. Last night I was going in circles in entirely the wrong direction. No more math after midnight on weekends for me. Thanks again. |
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| Author: | Hesh [ Sun Jan 25, 2009 9:31 am ] |
| Post subject: | Re: Stupid Algebra Question |
David Collins wrote: Thanks Christophe! That's it. Last night I was going in circles in entirely the wrong direction. No more math after midnight on weekends for me. Thanks again. Sounds like an exciting evening.......  Well at least you didn't lose your pocket protector..... Oh man I am in trouble now..... 
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| Author: | David Collins [ Sun Jan 25, 2009 10:55 am ] |
| Post subject: | Re: Stupid Algebra Question |
Okay, I just had to go through it again to make sure I wasn't loosing it. Though the answer was certainly right, I had to factor through in my own way. x / (x-1) = y x = y (x-1) x = xy-y x-xy = -y x (1-y) = -y x = -y / (1-y) x = y / (y-1) Same answer. I like how you go through it without crossing the variables back and forth, but for some reason this way seems a bit more tangible to me. Of course now I've had "Lobachevsky" going through my head all last night and this morning (for all you Tom Lehrer fans out there). Thanks again. Hesh - I lost my favorite calculator at the Cooper's Glen festival (my main calculator for almost 10 years). I just got a new one yesterday, and have been going through withdrawal. This is very important therapy..... |
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| Author: | K.O. [ Sun Jan 25, 2009 1:59 pm ] |
| Post subject: | Re: Stupid Algebra Question |
Hyperbolic geometry? Dang, I was hoping I was looking at a fuzzy logic set , (rate of change)... Dang, just a fuzzy brain #*@!.... |
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| Author: | K.O. [ Sun Jan 25, 2009 2:39 pm ] |
| Post subject: | Re: Stupid Algebra Question |
Hyperbolic poetry? There once was a man, Nagyvary Who aimed to resolve an old query So he whipped out his lucci Checked from Helmholtz to Chladni -At the store, just to find the best berry! Then he took it on home right that instant Pressed it right before starting to ferment Took a sip, then a belch Said "Look out Mr. Welch!" This great formula's covered by patent! How does this concern Stradivari? Well we're talking of sly Nagyvary Who found in the shellac Just a small tiny spack Tony's drool with a trace of mulberry! Now THAT's the secret to Stradivarius' tone. attrib to Dave Collins... Why did you take your calc(T.I. 85?) to a music festival? Thanks Christophe for graphing it, looks elegant and exclamatory at the same time to me. |
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| Author: | David Collins [ Sun Jan 25, 2009 6:57 pm ] |
| Post subject: | Re: Stupid Algebra Question |
K.O. wrote: Why did you take your calc(T.I. 85?) to a music festival? No, the simpler TI 30xIIa. Had most of what I used on a regular basis though. I don't get the question though. How could anyone go to a music festival without taking their calculator??? 
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| Author: | Darryl Young [ Sun Jan 25, 2009 8:15 pm ] |
| Post subject: | Re: Stupid Algebra Question |
Hewlett Packard and reverse polish notation RULES!!! <smile> |
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| Author: | K.O. [ Sun Jan 25, 2009 11:29 pm ] |
| Post subject: | Re: Stupid Algebra Question |
http://www.fractal-vibes.com/fm/index.html |
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| Author: | K.O. [ Sun Jan 25, 2009 11:57 pm ] |
| Post subject: | Re: Stupid Algebra Question |
The allegro found in the user gallery brings it back to stringed instruments. sort of. |
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| Author: | Mike OMelia [ Mon Jan 26, 2009 1:12 pm ] |
| Post subject: | Re: Stupid Algebra Question |
I think it is called a trancendental function. it is 1/x +1/y = 1 Mike |
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| Author: | Erik Hauri [ Mon Jan 26, 2009 4:57 pm ] |
| Post subject: | Re: Stupid Algebra Question |
Here you go David. 
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