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!

Please help me with these!

  1. Jun 19, 2004 #1
    I’ll appreciated very much if anyone can help me with any of these following proves by any means. Thank you!

    1. y=ln|x| = y'=1/x

    2. lim ln|x|=+ infinity as x approaches toward positive infinity and-
    lim ln|x| = - infinity as x approaches 0 from positive side
  2. jcsd
  3. Jun 19, 2004 #2
    Maybe something like this... Let f(x) = exp(ln(x)), where exp(x) = e^x. Using the chain rule, we have that f'(x) = exp(ln(x)) * d/dx(ln(x)) = x * d/dx(ln(x)). But since f(x) = x, we must also have f'(x) = 1. Thus x * d/dx(ln(x)) = 1, or d/dx(ln(x)) = 1/x.
  4. Jun 19, 2004 #3
    Thank you Muzza! That was beautiful! How about my second problem?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Please help me with these!
  1. Please Help Me! (Replies: 3)

  2. Percentage homework (Replies: 3)