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Homework Help: The chain rule

  1. Mar 31, 2009 #1
    1. The problem statement, all variables and given/known data
    Hi all.

    I have an expression given by V(x,y) = ay+x2y2, where a is a constant. I wish to find the time-derivative of V(x,y), and this is what I have done:

    \frac{dV}{dt} = a\dot y + \frac{d}{dt}x^2y^2,
    where the dot over y represents differentiation w.r.t. time. My problem is the last term, and I wish to use the chain-rule, but I am not sure how to use it. Can you give me a push in the right direction?

    Thanks in advance.

    Best regards,
  2. jcsd
  3. Mar 31, 2009 #2
    Apply the product rule first to x^2.y^2
  4. Mar 31, 2009 #3
    Do you know how to do:
    (Assuming x is a fuction of t)
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