Vector equations of lines in R2

This applet shows a line in ℝ2 and the vector form of its equation. A vector equation for a line has the form r = r0 + tv, t ∈ ℝ where r0 is the position vector of a point on the line, and v is a vector parallel to the line. You can click and drag r0 and v to adjust the line.  Try modifying both r0 and v in turn, to see what the resulting lines have in common. If you select the “Constrain points to line” checkbox, the line will be locked in place, and r0 and v will only be able to be moved along the line. This allows you to see that the same line can have many possible vector equations.