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: Solving limit

  1. Dec 13, 2009 #1
    1. The problem statement, all variables and given/known data
    Find

    limit ......(1-cos(2x^2)) / (1-cos(3x^2))
    x->0

    2. The attempt at a solution
    since the above gave me 0/0, I used l'Hopital method..
    then i got

    (4x)sin(2x^2) / (6x)(sin3x^2)
    which gives me 0/0 again..

    so I kept on using l'Hopital.. but it seemed on going forever

    is there other way to solve this..?
    thank you in advance
     
  2. jcsd
  3. Dec 13, 2009 #2

    LCKurtz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Don't keep using LH rule. Remember you know (at least you should know):

    [tex]\lim_{x\rightarrow 0}\frac {\sin x} x = 1[/tex]

    See if you can figure out how to use that next.
     
  4. Dec 13, 2009 #3
    Using LH twice doesn't give 0/0.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook