# Equations of slope?

1. Feb 15, 2009

### alliereid

What is the defining equation of the concept of slope?

I thought it could be rise / run = m or Y2-Y1 / X2-X1 = m but then the next question asks to give the two common forms of the mathematical equation for slope involving X and Y? So would that not be those two equations?

2. Feb 15, 2009

### Miney

I would say the the equation they are looking for would be:

Slope/gradient (m) = y2-y1 / x2-x1

Not sure what the other one would be...Unless you're doing calculus in which case it could be the derivative (slope) at a particular point.

eg. f'(x) = 2x^2 + 1 at the point where x=2

Therefore you have both your 'x' value and 'y' value because technically f(x) = y

Hope that helped...

3. Feb 15, 2009

### davieddy

sin or tan of the angle of slope are both commonly used

4. Feb 15, 2009

### Redbelly98

Staff Emeritus
Sometimes the Greek letter Δ is used to signify the change in a quantity or variable. That might be what they are looking for.