Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Quick (dumb) Notation Question

  1. May 21, 2009 #1

    AOA

    User Avatar

    I know writing [tex]\frac{\partial^{1}u}{\partial x^{1}}[/tex] is "bad" notation, but can I still write the sum:

    [tex]\sum^{n}_{k=1}\frac{\partial^{k}u}{\partial x^{k}}[/tex]

    ??

    THANK YOU

    PS. Being able to write LaTeX equations is actually awesome.
     
  2. jcsd
  3. May 22, 2009 #2

    CompuChip

    User Avatar
    Science Advisor
    Homework Helper

    When you write it explicitly it looks a bit weird, but I see no objection to using it in such a sum.
     
  4. May 22, 2009 #3

    AOA

    User Avatar

    OK. I just wanted to make sure. Thanks!
     
  5. May 22, 2009 #4
    Can I ask what kind of situation you're getting that sum in?
     
  6. May 22, 2009 #5

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    While uncommon, I don't see anything bad about it.

    When dealing with just the first derivative of some function, it is superfluous, but completely analogical to the case that [itex]x=x^{1}[/itex]
    Neither of these two notations are "bad" in any way.
     
  7. May 22, 2009 #6

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    I would even accept
    [tex]\sum_{k=0}^n \frac{\partial^k u}{\partial x^k}[/tex]
    with the understanding that
    [tex]\frac{\partial^0 u}{\partial x^0}= u(x)[/tex]
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Quick (dumb) Notation Question
Loading...