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!

Confused on this notation! partial derivatives!

  1. Oct 19, 2005 #1
    Hello everyone I have no idea how to start this problem because i'm confused on the notation, what does it mean?
    here is a picture:
    http://img291.imageshack.us/img291/1177/lastscan2lc.jpg [Broken]
    I know how to take partial derivatives, but the d^2 part is confusing and the dx^2? what the!
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Oct 19, 2005 #2
    The "d^2/dt^2" part means it is a second order derivative. It basically means how many times you take that derivative.

    So when you have: [tex] \frac{d^1 x^2}{dx^1}[/tex] then this means... take the derivative of x^2 one time. So you get 2x.

    Now if you you had [tex] \frac{d^2 x^2}{dx^2} [/tex] then this means you take the derivative twice. So in TI-89 syntax you would have:


    which equals 2.
  4. Oct 19, 2005 #3


    User Avatar
    Homework Helper

    It may be a but confusing at first, but you'll get used to it. Note that the "square" is at the 'd'-sign in the numerator and above the x (or any other variable) in the denominator. Of course, we still mean the variable x, and not x². In the nominator, it still has to be clear that we're differentiating f, and not f².

    So (I'm using normal derivatives here, not partials, but the notation is similar)
    [tex]\frac{{d^2 f}}{{dx^2 }} = \frac{d}{{dx}}\left( {\frac{{df}}{{dx}}} \right)[/tex]

    But watch out, not one of the following:
    [tex]\frac{{df^2 }}
    {{dx^2 }},\frac{{d^2 f}}
    {{d^2 x}},\frac{{df^2 }}
    {{d^2 x}}[/tex]
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Confused on this notation! partial derivatives!