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Math Help - urgent help on limits

  1. #1
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    urgent help on limits

    45.)
    \lim_{x \to -1} \frac {2x^2-x- 3}{x^3+2x^2+6x+5} = ?
    Last edited by ^_^Engineer_Adam^_^; November 23rd 2006 at 03:04 PM.
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  2. #2
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    Quote Originally Posted by ^_^Engineer_Adam^_^ View Post
    45.)
    \lim_{x \to 1} \frac {2x^2-x- 3}{x^3+2x^2+6x+5} = ?
    Because both the numerator and denominator are well behaved at x=1 the limit may be evaluated by substituting 1 for x so:

    <br />
\lim_{x \to 1} \frac {2x^2-x- 3}{x^3+2x^2+6x+5} = \frac{-2}{14}=-\frac{1}{7}<br />

    RonL
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  3. #3
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    sorry for my mistake 45 is \lim_{x \to -1}
    thank u very much!
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  4. #4
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    Quote Originally Posted by ^_^Engineer_Adam^_^ View Post
    45.)
    \lim_{x \to -1} \frac {2x^2-x- 3}{x^3+2x^2+6x+5} = ?
    In this case both the numerator and denominator are 0. Thus we may use L'Hopital's rule:

    \lim_{x \to -1} \frac {2x^2-x- 3}{x^3+2x^2+6x+5} = \lim_{x \to -1} \frac {4x - 1}{3x^2 + 4x + 6} = \frac{3}{5}

    -Dan
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  5. #5
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    \lim_{x\to\-1}\frac{2x^{2}-x-3}{x^{3}+2x^{2}+6x+5}=\lim_{x\to\-1}\frac{(x+1)(2x-3)}{(x+1)(x^{2}+x+5)}=\lim_{x\to\-1}\frac{2x-3}{x^{2}+x+5}=-1

    That supoosed to be a -1 under the limit symbol, but for some reason it won't display.
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  6. #6
    Member Ranger SVO's Avatar
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    I'm gonna go with galactus
    Attached Thumbnails Attached Thumbnails urgent help on limits-screen01.jpg  
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  7. #7
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by topsquark View Post
    In this case both the numerator and denominator are 0. Thus we may use L'Hopital's rule:

    \lim_{x \to -1} \frac {2x^2-x- 3}{x^3+2x^2+6x+5} = \lim_{x \to -1} \frac {4x - 1}{3x^2 + 4x + 6} = \frac{3}{5}

    -Dan
    You know, you'll get MY answer if you put x = 1 in the numerator and x = -1 in the denominator...

    -Dan
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  8. #8
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    Quote Originally Posted by Ranger SVO View Post
    I'm gonna go with galactus
    Hello Ranger SVO.

    May I ask, if it's not too much trouble, how you managed to post the screen from your Voyage 200?. I have a TI-92 with the GraphLink; I have my programs backed up and so forth, but I've not done that. I know if I try, I'll probably get some annoying error message.
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  9. #9
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    Quote Originally Posted by galactus View Post
    Hello Ranger SVO.

    May I ask, if it's not too much trouble, how you managed to post the screen from your Voyage 200?. I have a TI-92 with the GraphLink; I have my programs backed up and so forth, but I've not done that. I know if I try, I'll probably get some annoying error message.
    I am guessing he has a cable that attaches to a computer. Then it displays on the screen. He took a screenshot.
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  10. #10
    Eater of Worlds
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    Oh, O.K., PH. I'll try that.

    Thanks, PH, It actually worked.
    Last edited by galactus; November 24th 2006 at 07:55 AM.
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  11. #11
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    if you are allowed use l'hopital rule
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  12. #12
    Member Ranger SVO's Avatar
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    Quote Originally Posted by galactus View Post
    Hello Ranger SVO.

    May I ask, if it's not too much trouble, how you managed to post the screen from your Voyage 200?. I have a TI-92 with the GraphLink; I have my programs backed up and so forth, but I've not done that. I know if I try, I'll probably get some annoying error message.

    TI Connect has a screen capture button, right next to Device Explorer.
    Right after you press, screen capture, in the tool bar is a copy button.
    I'll bet you got it from there
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  13. #13
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    That's what I done Ranger. I was glad it worked so slick.
    Last edited by galactus; November 24th 2008 at 05:39 AM.
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  14. #14
    Member Ranger SVO's Avatar
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    Quote Originally Posted by galactus View Post
    That's what I done Ranger. I was glad it worked so slick.
    I wonder if I have Greens Theorum on mine, I'll have to look now. I don't remember seeing it. Did you find that somewhere?
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  15. #15
    Eater of Worlds
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    That's a program I wrote a long time ago. I was playing with it at the time I used the screen capture.
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