1. Not finding help here? Sign up for a free 30min 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!

Absolute value in integral

  1. Dec 2, 2013 #1
    ∫tan(x) dx = -ln lcos(x)l + C = f(x)

    So is f'(x) = -sin(x)/lcos(x)l ? When taking the derivative, do we only consider f'(x) to only exist on the intervals where cos(x) > 0 instead?
     
  2. jcsd
  3. Dec 2, 2013 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    No, the derivative of log(|y(x)|) is the derivative of log(y(x)) if y(x)>0 and it's the derivative of log(-y(x)) if y(x)<0. Can you show that they are both (1/y(x))*y'(x). Not (1/|y(x)|)*y'(x)?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Absolute value in integral
Loading...