**Slope** is a rate of change in the dependent variable for a given change of the independent variable of a function.

The average slope, or slope of the secant line between x_{1} and x_{2}, can be computed using the formula:

- .

When a linear equation (with no powers other than one and zero) is written in slope-intercept form (), the slope is , the coefficient of .

To find the instantaneous slope of a function, or the slope of the tangent line at x_{0}, the limit as x approaches x_{0} can be taken.

This can be extended to every point on a curve by the formula

which is the definition of the derivative of f(x).