A partial derivative Question

Discussion in 'Math' started by shikhar623, Mar 5, 2015.

  1. shikhar623

    Thread Starter Active Member

    May 9, 2009
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    I am doing an online assignment and struck at this question. Please explain how to do it.
    Or better provide me the answer :)
     
    Last edited: Mar 6, 2015
  2. WBahn

    Moderator

    Mar 31, 2012
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    Or better yet, show YOUR work to get at an answer for YOUR assignment and then we can guide you through the problems you are making.
     
  3. shikhar623

    Thread Starter Active Member

    May 9, 2009
    31
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    It's an online assignment. There is no provision for the getting the answer. I have to either leave it or do it. Though the number of attempts are unlimited. Can you offer any help?
     
  4. WBahn

    Moderator

    Mar 31, 2012
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    Yes, we can offer help AFTER you show your efforts to answer it yourself. Do the work as best you can and present it here. We can then look at what you have done and point out where you are going right and where you are going wrong. But YOU have to do the work.
     
  5. shikhar623

    Thread Starter Active Member

    May 9, 2009
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    Dx2/dudv = 4
    Dy/dudv=3
    At u=5 v=4
     
  6. WBahn

    Moderator

    Mar 31, 2012
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    How do you get these?

    Start with what you want to know and then use the chain rule to expand it.
     
  7. shikhar623

    Thread Starter Active Member

    May 9, 2009
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    I want partial derivative of Z wrt to v. But how to write it without knowing the actual expression of Z? I am missing some point here.
     
  8. shikhar623

    Thread Starter Active Member

    May 9, 2009
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    Please Correct me if i am wrong.
     
  9. WBahn

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    Mar 31, 2012
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    You have

    <br />
z \; = \; f(x,y)<br />

    and you want

    <br />
\frac{\partial z}{\partial v} \; = \; \frac{\partial f(x,y)}{\partial v}<br />

    So what does the chain rule say about this in terms of the partial derivatives of f(x,y) with respect to x and y?
     
    Last edited: Mar 6, 2015
  10. shikhar623

    Thread Starter Active Member

    May 9, 2009
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    Thank you. I did it, but the time had lapsed.
     
  11. WBahn

    Moderator

    Mar 31, 2012
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    So what did you get for the answer?
     
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