Plane Through a Line and a Point
If a line is:
$$\vec r=\vec a+\lambda\vec b$$
and a point has position vector $$\vec c$$, then a normal vector to the required plane is:
$$\vec n=\vec b\times(\vec c-\vec a)$$
Hence:
$$(\vec r-\vec a)\cdot[\vec b\times(\vec c-\vec a)]=0$$
Usage
- Used to find the unique plane containing a line and a point not on that line.