Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Advice for derievative

  1. Aug 19, 2008 #1
    1. The problem statement, all variables and given/known data

    Find dc/dp and dc/dq.

    2. Relevant equations

    c= (2p/q)-1/2

    3. The attempt at a solution

    I just want to make if I'm right. I got...
    dc/dp = (2/q)-1/2

    dc/dq = [-2p/(q^2)] -1/2

    Thanks.
     
  2. jcsd
  3. Aug 19, 2008 #2
    Re: derievative

    Hi,
    There is an error in your use of the chain rule:
    [tex] \frac{dc}{dp}=-\frac{1}{2}\left(\frac{2p}{q}\right)^{-\frac{3}{2}}\cdot\left(\frac{2q-0}{q^2}\right)[/tex]
    then simplify.

    Same thing for dc/dq:
    [tex]\frac{dc}{dq}=-\frac{1}{2}\left(\frac{2p}{q}\right)^{-\frac{3}{2}}\cdot\left(\frac{0-2p}{q^2}\right)[/tex]
    then simplify.
     
    Last edited: Aug 19, 2008
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook