Following are the steps to find out whether points ** A**,

- Calulate vectors \(\vec{AB}\) and \(\vec{AC}\)
- The points are collinear if the following is true

\(\frac{\vert \vec{AB} \cdot \vec{AC}\vert}{\vert\vec{AB}\vert \vert\vec{AC}\vert}=1\) - Alternatively, the points are collinear if the following is true

\(\vec{AB} \times \vec{AC}=0\)

In 2D only, 3 points (x

\(\begin{vmatrix} x_1 & y_1 & 1 \\ x_2 & y_2 & 1 \\ x_3 & y_3 & 1 \end{vmatrix}=0\)