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Homework Help: Differentiating product

  1. Jan 22, 2010 #1
    Hi,

    I need to differentiate the following [tex]\frac{d}{dx}[e^{-2x}y][/tex]

    Does the `dx` mean that the y turns into x?

    I know i have to use the product rule.
     
  2. jcsd
  3. Jan 22, 2010 #2

    tiny-tim

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    Hi James889! :smile:

    No, you just write "dy/dx" …

    d/dx ( f(x)y) = f'(x)y + f(x)dy/dx :wink:
     
  4. Jan 22, 2010 #3
    Hm?, what do you mean `just write`?

    I can't think of anyone i hate more than Wilhelm Leibniz, for coming up with this stupid notation :mad:
     
  5. Jan 22, 2010 #4

    tiny-tim

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    he he, get used to it! :biggrin:

    (it's particularly useful when you start using substitution of variables in integals)

    of course, you could write " y' " instead. :wink:
     
  6. Jan 22, 2010 #5

    Mark44

    Staff: Mentor

    Personally, I prefer Leibniz notation over Newton's notation as being more informative. The notation dy/dx is lots more informative than, say y' inasmuch as the Leibniz notation tells you exactly which variable with which differentiation is with respect to.
     
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