Slope

The slope of a line is a measure of its steepness. Mathematically, slope is calculated as “rise over run”. Each line has a different slope depending on whether it is vertical or horizontal. The difference is that a horizontal line is always 0 because in rise over anything divided by 0 is 0. Vertical line is always undefined because it does not run horizontally.

Equation

The equation of a horizontal line is y=something. The equation of a vertical line is x=something.

Function/not a function 

When it comes to a function, horizontal and vertical lines are very different. To judge whether the line is a function or not a function is dependent on the vertical line test. To do the vertical line test you can use a pencil/ruler and move it across your paper to see if the pencil/ruler to see if it touches more than one point. Horizontal lines are function because they don’t touch more than one point and are not one-one and vertical lines are a function because they touch more than one point.

Domain & Range

A vertical lines range is infinite while its domain is somewhere on the x-axis. A horizontal lines range is somewhere on the y-axis and the domain is infinite this is because its slope is zero.

Examples of all

Slope &

Slope & domain and range:

Function/not a function

Not a function:

Function: