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!

Notation - f(x,a) vs f(x;a)

  1. Mar 10, 2010 #1
    1. The problem statement, all variables and given/known data

    Quick question...

    I have seen both being used : f(x,a) and f(x;a). What is the usual convention? Are both acceptable to denote functions of 2 variables (in this case f is a function of both x and a). Or are there vital differences between the two that I don't know about?

    Thanks! :)

    2. Relevant equations


    3. The attempt at a solution

  2. jcsd
  3. Mar 10, 2010 #2


    Staff: Mentor

    I don't recall ever seeing this notation -- f(x; a) -- being used.
  4. Mar 10, 2010 #3


    User Avatar
    Homework Helper

    notation like [tex] f(x;a) [/tex] is used in mathematical statistics when you want to show that a distribution depends on a parameter (real or vector-valued). for example, if you are talking about a normal distribution with some mean and standard deviation, writing
    [tex] \theta = (\mu, \sigma)[/tex] the density would be indicated [tex] f(x;\theta)[/tex]

    it indicates that the function depends on [tex] x [/tex] and involves a parameter [tex] \theta [/tex] (so, as we say in statistics, by varying [tex] \theta [/tex] we obtain not one but a family of normal distributions.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook