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Homework Help: Which of the following has y=-1 as an asymptote?

  1. Jul 2, 2008 #1
    Which of the following has y=-1 as an asymptote?
    1.e^(-x)
    2.sin(x)
    3.ln x
    4.x/(x+1)
    5.(3-2x^2)/(2x^2-13x+7)

    I've graphed each one on my calculator and I think that 1 is the answer, but it seems that it has y=0 as its asymptote rather than y=-1.
     
  2. jcsd
  3. Jul 2, 2008 #2
    Re: asymptote

    Your calculator sucks.

    Where's your work?
     
  4. Jul 3, 2008 #3
    Re: asymptote

    I only used my calculator, but I thought about it for #4, asymptote should be x=-1 and for sin(x) there is definitely an x value for y=-1.
     
  5. Jul 3, 2008 #4
    Re: asymptote

    Are you on a 2nd username?
     
  6. Jul 3, 2008 #5
    Re: asymptote

    Sorry, I went on my brother's account by mistake.
     
  7. Jul 3, 2008 #6
    Re: asymptote

    It's okay, it was just funny to read your post as if you were pooka.

    Anyways, yes sinx has the value y=-1 but would that be considered an asymptote? It bounces between [tex]|\sin x|\leq 1[/tex]

    How about #5? What have you learned about the powers in the numerator and denominator that relate to the asmyptote?
     
  8. Jul 3, 2008 #7
    Re: asymptote

    Oh so the answer should be #5. I remember if you took the limit of that it would be -1, which means the horizontal asymptote is y=-1.
     
  9. Jul 3, 2008 #8
    Re: asymptote

    Yep.

    [tex]\lim_{x\rightarrow\pm\infty}\frac{3-2x^2}{2x^2-3x+7}[/tex]
     
  10. Jul 3, 2008 #9
    Re: asymptote

    Thanks!:smile:
     
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