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!

How do you differentiate this

  1. Mar 20, 2007 #1
    x^2y

    the y is biglike the x its not small

    and how do you differentiate this
    xy^2

    for the first one i used the product rule and thesecond one and i get a different answer then what i was suppost to get
     
  2. jcsd
  3. Mar 20, 2007 #2
    for the first one i didthis

    x^2 d/dx y dy/dx + y d/dx x^2

    x^2 y' + y+ 2x

    so how come im not getting 2x 2y
     
  4. Mar 20, 2007 #3
    :confused: You need an equation, not an expression, i.e. [tex]x^{2}y = ?[/tex]. Also, are you familiar with implicit differentiation?
     
    Last edited: Mar 20, 2007
  5. Mar 20, 2007 #4
    ill give u the equation x^3+x^2y+4y^2=6
     
  6. Mar 20, 2007 #5
    i understand it now, the answer of this was factored out or cleaned up a bit, so i didn't notice there was an x outside of the paranthesis of 2y
     
  7. Mar 20, 2007 #6
    [tex]x^3 + x^2y + 4y^2 = 6[/tex]

    Okay, but do you know what implicit differentiation is? For example,

    [tex]x + y = 1 [/itex]

    [tex]\frac{dx}{dx} + \frac{dy}{dx} = \frac{d1}{dx} [/tex]

    [tex]1 + \frac{dy}{dx} = 0 [/tex]

    Also for a product, the product rule applies, e.g.

    [tex]xy = 1[/tex]

    [tex]x*\frac{dy}{dx} + \frac{dx}{dx}*y = 0 [/tex]
     
    Last edited: Mar 20, 2007
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?