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Can anyone help me with this math problem?

  1. Jan 8, 2007 #1
    It looks like this:

    1 1
    __ - _
    1-t t
    1 1
    __ - _
    1+t t

    Sorry if that looks strange. =/

    I got it down to this:


    I have no idea if that's right though, and I don't know where to go from there.

    I'm really sorry if this is off topic.

    It's a friend of mine who needs the help, and I have no idea what type of math this is, so I thought some great mind here could help her out. :biggrin:
  2. jcsd
  3. Jan 8, 2007 #2
    I'm also having problems with a word problem. I think I set it up right... but I'm not getting to a solution that can be worked out. x_x At least. This doesn't look easily solvable:
    .5x² + 50x - 280000 = 0

    I'll try it a different way...
  4. Jan 8, 2007 #3


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    Staff: Mentor

    Thread moved from Physics to Math. Isolex, use the Binomial Theorm to solve this. Look it up at wikipedia.org if you don't have it in your textbook for some reason.

    And the math in your first post is hard to follow with the way you've laid it out. Can you maybe re-try and just put each equation on one line and use parenthesis to show the groupings? (Better yet would be to use LaTex as described in the Tutorials forum, but we can leave that for later....)
  5. Jan 8, 2007 #4

    We solved the word problem, thanks to you!

    We're going to try to make a picture for the other one.
  6. Jan 8, 2007 #5
  7. Jan 8, 2007 #6
    Er. That didn't work. Lol.

    But yeah, there's the problem. :D
  8. Jan 8, 2007 #7

    Sorry, I'm just playing around and figuring this out. Heh.
  9. Jan 8, 2007 #8
    That's right so far.

    But what is it supposed to equal? Otherwise you can't solve it.

    But to simplify it further, use the fact that

    [tex]\frac{\frac{a}{b}}{\frac{c}{d}} = \frac{ad}{bc}[/tex]
  10. Jan 8, 2007 #9

    Gib Z

    User Avatar
    Homework Helper

    [tex] \frac {\frac {1}{1-t} - \frac {1}{t}}{\frac {1}{1+t} - \frac {1}{t}}[/tex].

    Multiply the whole fraction by t/t, which is just one. One times anything is the same thing. Once we times it by t/t we get:

    [tex]\frac{\frac{t}{1-t} -1}{\frac{t}{1+t}-1}}[/tex]

    Times it all by (t+1)/(t+1), since thats just one again.

    We get:
    [tex]\frac{\frac{t(t+1)}{1-t} - (t+1)}{t-(t+1)}[/tex].

    As you Can see, the bottom cancels out to 1.

    We are left with
    [tex]\frac{t(t+1)}{1-t} - (t+1)}[/tex]

    Multiply the 2nd part, -(t+1), by (1-t/(1-t), since thats just 1. Then put it all on one big fraction.

    [tex]\frac{t(t+1) - (1-t)(t+1)}{1-t}[/tex]

    Bring the (t+1) terms together, and we get our simplest form of the equation:

    << Last result deleted by berkeman >>

    Hope that helps :)
    Last edited by a moderator: Jan 9, 2007
  11. Jan 9, 2007 #10


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    Staff: Mentor

    Gib_Z, remember not to post complete solutions in the homework forums. Our job here (according to the PF rules that you agreed to) is to provide hints and guidance, not complete solutions.

    I'm going to leave your post, however (except I deleted your final result). This is a simple enough problem and you did a nice job with LaTex, so it will probably help the OP in this case to learn how to work the problem. In the future, leave most of the final steps out -- just provide a framework that helps the OP to get going.
    Last edited: Jan 9, 2007
  12. Jan 9, 2007 #11

    Gib Z

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    Homework Helper

    Sorry about that, I didn't actually read the rules..Ill make sure I adhere to them now. Thats for not deleting my post, the LaTex did take a while :) ty
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