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

Homework Help: What does the . in equations stand for?

  1. Mar 22, 2008 #1
    What does the "." in equations stand for?

    I've been revising electric fields, and have come across the equation [tex] \Delta E_{p} = k . Q_{1} Q_{2} [ \frac{1}{r_{1}} - \frac{1}{r_{2}}] [/tex]

    I have never come accross a decimal point in an equation before, what does it mean?
    Last edited: Mar 22, 2008
  2. jcsd
  3. Mar 22, 2008 #2


    User Avatar
    Homework Helper

    "." is another way of saying "multiplied by"
  4. Mar 23, 2008 #3


    User Avatar

    It is to avoid using [itex]\times[/itex] which can be used to represent a variable. It would cause confusion hence a dot is used to show multiplication.
  5. Mar 23, 2008 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Note, it's not a period, as in [ilatex]a . b[/ilatex], it's a midline-dot, like [ilatex]a \cdot b[/ilatex]

    - Warren
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook