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!

Find the derivative of arctan(6x)

  1. Mar 10, 2009 #1
    1. The problem statement, all variables and given/known data
    Find the derivative of arctan(6x).


    2. Relevant equations



    3. The attempt at a solution
    Ok, I know the derivative of arctan(x) is 1/(x^2 + 1).

    So I am trying to make the substitution u = 6x.

    Then the derivative of arctan(u) should be 1/(u^2 + 1)... and therefore 1/(36x^2 +1).

    But that's not right... what am I doing wrong?
     
  2. jcsd
  3. Mar 10, 2009 #2

    lanedance

    User Avatar
    Homework Helper

    if you make the subsitition u(x) = 6x

    then you have
    [tex] \frac{d}{dx} arctan(u(x)) [/tex]

    so you need to use the chain rule...
     
  4. Mar 10, 2009 #3
    I can't read your equation...
     
  5. Mar 10, 2009 #4
    Okay, so:

    1/(u^2 +1) multiplied by the derivative of u?
     
  6. Mar 10, 2009 #5

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    Yes. And since u= 6x, its derivative is ?
     
  7. Mar 10, 2009 #6
    6/(36x^2 +1)?

    Thank you!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Find the derivative of arctan(6x)
  1. Derivative of arctan (Replies: 4)

  2. Arctan Derivative (Replies: 10)

Loading...