What is an example of direct proportionality?

sotellme · Dec 14, 2004

directly proportional? can anyone give an example of it?

thanks alot!

Pyrrhus · Dec 14, 2004

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

y = Ax

\frac{y}{x} = A

Sirus · Dec 14, 2004

Right. This is represented as y\propto x.

sotellme · Dec 14, 2004

thanks!

cyby · Dec 14, 2004

Careful. Make sure A is not a positive constant < 1. Otherwise you will get that they are inversely proportional.

sotellme · Dec 14, 2004

cyby said:

Careful. Make sure A is not a positive constant < 1. Otherwise you will get that they are inversely proportional.

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:

quantumdude · Dec 14, 2004

cyby said:

Careful. Make sure A is not a positive constant < 1. Otherwise you will get that they are inversely proportional.

No, that's not true. It's still a direct proportion. y and x are inversely proportional if y=A/x.

cyby · Dec 14, 2004

Uh, you are right. Sorry, was thinking about something else completely.