m = undefined
For a vertical line, we have the same point of x-axis.
What this mean is that there is no change on the x-axis.
An example is shown below;
Find the slope of the line AB;
We can see the line AB as a vertical line
Mahematically, the formula for the slope of a line is given as;
[tex]m\text{ = }\frac{y_2-y_1}{x_2-x_1}[/tex]
But in the case of a vertical line;
[tex]x_2=x_1[/tex]
So what this mean is that, we rewrite our formula for the slope as;
[tex]m\text{ = }\frac{y_2-y_1}{x_2-x_2}\text{ = }\frac{y_2-y_1}{0}[/tex]
But since the division of any number with zero as the denominator is 'undefined"
The slope m in this case is undefined
