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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

    Pyrrhus

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    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

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    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.
     
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