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

Directly proportional?

  1. Dec 14, 2004 #1
    directly proportional? can anyone give an example of it?

    thanks alot!
  2. jcsd
  3. Dec 14, 2004 #2


    User Avatar
    Homework Helper

    y and x are directly proportional, A is a constant.

    [tex] y = Ax [/tex]

    [tex] \frac{y}{x} = A [/tex]
  4. Dec 14, 2004 #3
    Right. This is represented as [tex]y\propto x[/tex].
  5. Dec 14, 2004 #4
    thanks! :smile:
  6. Dec 14, 2004 #5
    Careful. Make sure A is not a positive constant < 1. Otherwise you will get that they are inversely proportional.
  7. Dec 14, 2004 #6

    hi cyby! what you mean with that? do you mean that A must always be a positve number if not it will be inversely proportional? :cry:
  8. Dec 14, 2004 #7

    Tom Mattson

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    No, that's not true. It's still a direct proportion. y and x are inversely proportional if y=A/x.
  9. Dec 14, 2004 #8
    Uh, you are right. Sorry, was thinking about something else completely.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Directly proportional?