Slope
Vertical lines have undefined slope. When doing rise over run, the run will always be 0. Because the undefined slope will always rise and not run.
Ex. a undefined slope
![](https://mycentennial.sd43.bc.ca/johndavidc2020/files/2021/11/desmos-graph-1-4.png)
Horizontal lines have a zero slope. When doing rise over run, the rise will always be 0. Because the zero slope will always run and not rise.
Ex. a zero slope
![](https://mycentennial.sd43.bc.ca/johndavidc2020/files/2021/11/desmos-graph-2.png)
Equation
Whenever x=___ whatever the x intercept is it will always be a vertical line. Because it doesn’t have a y point and the line will be drawn on the intercept of the line.
Ex. (3,7) x=3
![](https://mycentennial.sd43.bc.ca/johndavidc2020/files/2021/11/desmos-graph-1-1.png)
Whenever y=___ whatever the y-intercept is it will always be a horizontal line. Because it doesn’t have a x point and the line will be drawn on the intercept of the line.
Ex. (7,3) y=3
![](https://mycentennial.sd43.bc.ca/johndavidc2020/files/2021/11/desmos-graph-2-1.png)
Functions
All undefined slopes will not be a function because it will fail the vertical line test since it always has more that one point
Ex.
![](https://mycentennial.sd43.bc.ca/johndavidc2020/files/2021/11/desmos-graph-1-3.png)
All zero slopes will be a function but not one to one because it won’t fail the vertical line test but it fails the horizontal test.
Ex
![](https://mycentennial.sd43.bc.ca/johndavidc2020/files/2021/11/desmos-graph-2-3.png)
Domain & Range
The domain of a undefined slope will always be x=___ whatever the x-intercept is and the range will be all real numbers. Because the domain only hits the x-intercept and the range is all real numbers because it will continuoesly go up and down.
Ex. Domain: x=3 Range: All real #’s
![](https://mycentennial.sd43.bc.ca/johndavidc2020/files/2021/11/desmos-graph-1-2.png)
The range of a zero slope will always be y=___ whatever the y-intercept is and the domain will be all real numbers. Because the range only hits the y-intercept and the range is all real numbers because it will continuoesly go left and right.
Ex. Domain: All real #’s Range: y=3