# Directly proportional?

#### sotellme

directly proportional? can anyone give an example of it?

thanks alot!

#### Pyrrhus

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

$$y = Ax$$

$$\frac{y}{x} = A$$

#### Sirus

Right. This is represented as $$y\propto x$$.

thanks!

#### cyby

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

#### sotellme

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?

#### Tom Mattson

Staff Emeritus
Gold Member
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

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