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!

Limit help

  1. Sep 12, 2005 #1
    lim(x->pi/4) tan(2x) =tan(pi/2) wat to do after this, it is undefined
  2. jcsd
  3. Sep 12, 2005 #2
    tan(pi/2) is undefined but the limit is not. take a look at a graph of tan(x) and see whats going on just to the left or right of pi/2.
  4. Sep 12, 2005 #3


    User Avatar
    Gold Member

    Actually the limit is not defined. As x approaches [itex]\frac{\pi}{2}[/itex] from the left, the function approaches infinity. As x approaches from the right, the function approaches negative infinity. The limit from the left does not equal the limit from the right, so the limit does not exist. Actually, strictly speaking, the limit would not exist even if the function approached positive infinty from both sides, since the definition of the limit requires that the function get arbitrarily close to the limit, and it is impossible for a function to be within some definite value of infinty.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Limit help
  1. Limits help (Replies: 4)

  2. Help with a limit (Replies: 3)

  3. Limits help! (Replies: 3)

  4. Help with a limit (Replies: 9)

  5. Limits help! (Replies: 3)