Parametric form of a line

The parametric form of a line represents it using two vectors: an arbitrary point equation on the line and the direction vector equation:

    equation

By choosing a value for the scalar equation, we can reach any point on this line. We can show this graphically as follows:

line

Example of a line

To find the parametric line equation given two points equation and equation, we only have to calculate the direction vector equation which we obtain by subtracting one point from the other:

(1)   equation