1. Limited time only! Sign up for a free 30min personal 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!

What's difference between (∂y/∂x) and (dy/dx)

  1. Mar 27, 2009 #1
    Hi all.
    Can anyone tell me what's difference between (∂y/∂x) and (dy/dx) and (fx) and (y`)?

    Thanks.(please tell me my probable English mistakes!)

    I asked this a few month ago but it seems that images in topic are not avaible (I think I have removed it from my server )
     
  2. jcsd
  3. Mar 27, 2009 #2
    ∂y/∂x and fx are http://en.wikipedia.org/wiki/Partial_derivative" [Broken]. They are applied to functions of several real variables, for example f(x,y)=x2+y2.

    dy/dx or y' is the ordinary derivative of a function of a single real variable such as y(x)=1/x.
     
    Last edited by a moderator: May 4, 2017
  4. Mar 27, 2009 #3
    Thank you.
    and another question:
    I have read this in my book =>
    v=y/x
    dv/dx=....

    My question is : although V function has more than one variable why the author has used (dv/dx) instead of ∂v/∂x?(y and x are variables)
    (you said that dy/dx is used when there is a single variable).
     
  5. Mar 27, 2009 #4

    Mark44

    Staff: Mentor

    v = y/x is a commonly used substitution for solving differential equations that involve y and x. It is assumed that y is a function of x. Although v is in terms of y and x in the substitution, v is ultimately a function of x, so it's reasonable to write its derivative as dv/dx

    In functions of two or more variables, as yyat mentioned, it is not assumed that any one independent variable is related to any other independent variable.
     
  6. Mar 28, 2009 #5
    Thank you all.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: What's difference between (∂y/∂x) and (dy/dx)
  1. Solving dy/dx=x-y (Replies: 4)

  2. Find dy/dx if f(x,y) = 0 (Replies: 11)

  3. Solve dx/y = dy/x (Replies: 11)

Loading...