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!

Differentiation check ?

  1. Nov 29, 2006 #1
    I should know this, but i just wanted to check....differentiating ln(3y-2z) with respect to z...............does this = -1/2z ???
     
  2. jcsd
  3. Nov 29, 2006 #2
    You must differentiate the whole thing first, then differentiate what is on the inside.

    To check your answer take the integral of -1/2z, you will see it is not equal ln(3y-2z)
     
  4. Nov 29, 2006 #3

    radou

    User Avatar
    Homework Helper

    As KoGs suggested, an appropriate use of the chain rule should do just fine.
     
  5. Nov 29, 2006 #4
    ok so is it -2/3y + z
     
  6. Nov 29, 2006 #5

    radou

    User Avatar
    Homework Helper

    No, it is not. As mentioned before, try to apply the chain rule:http://mathworld.wolfram.com/ChainRule.html
     
  7. Nov 29, 2006 #6
    I did apply it............this is how i calculated that result:

    d/dz In(3y-2z)
    y=In u therefore dy/du = 1/u
    u=3y-2z therefore du/dz = -2
    dy/du x du/dz = -2/(3y-2z)

    where am i going wrong?
     
  8. Nov 29, 2006 #7

    radou

    User Avatar
    Homework Helper

    Now you're not going wrong, since the result is correct. Good work! :wink:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?