1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: How to find horizontal asymptotes?

  1. Nov 22, 2012 #1
    1. The problem statement, all variables and given/known data


    2. Relevant equations

    3. The attempt at a solution

    I know you can usually compare the top and bottom and determine that way but how can you do it when it's like this? I know the answer is 0 already i dont know how to get it though
  2. jcsd
  3. Nov 22, 2012 #2
    Do you see how you might be able to re-write this and then use L'Hospital's Rule?

    Just as a side note, I hope you realise that there is no horizontal asymptote as x goes to positive infinity.
  4. Nov 22, 2012 #3
    ah i think i got it.

    do you end up with -4/(-1/e^(-x)) which basically is equal to -4/-infinity = 4/infinity = 0?
  5. Nov 22, 2012 #4
    Yes, but just to say it again, it is not as x goes to positive infinity.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook