Slope

The slope for a vertical line is rise/run=0 that equals rise/0 this line is an undefined line because when a number is divide by 0 it is undefined. This means that a vertical line will be the x intercept because the slope is undefined. The slope for a horizontal line is rise=0/run that is 0/run this line is a zero slope because when a number is divided by 0 it equals 0. The horizontal line then will then be the y intercept because the slope is 0.

A horizontal line with a zero slope

A vertical line with a undefined slope

Equation

The equation of a vertical line is X=__ when the line goes through a point for example (2,5) the equation would be X=2 because the slope for a vertical line is undefined. The equation of a horizontal line is Y=__ when the line goes through a point for example (4,7) the equation would be Y=7 because the slope is a zero slope.

Function not a Function

A horizontal and vertical line can be a function if they pass the horizontal and vertical line test. You use the vertical line test to determine if the line is a function by putting a vertical line through the whole graph and if two points of the line touch the vertical line it isn’t a function. The horizontal test is to determine if the line is a one to one function. A vertical line though isn’t a function because when you do the vertical line test on it the line touches more than once on the line. A horizontal line is a function because when you put it through the vertical test it doesn’t touch the line twice it is not a one to one function because it doesn’t pass the horizontal test.

Domain and Range

The domain and range for a vertical and horizontal line. A vertical line would be domain with the value of X=__ the blank would be the x intercept on the axis. The equation for a vertical line won’t have two numbers it will only have one number where the x intercepts. The Y would be all real numbers because it is a continuous line that goes on forever. For example X=3 the line will go through 3 on the x axis the y would be all real numbers.

A horizontal line is Y so it would be range with a value of Y=__ the blank will be the y intercept this time on the Y axis. the horizontal line will have one value that goes through continuously forever and the domain would be all real numbers for example Y=3.