If $\displaystyle n $ is a normal vector of a plane, then it is perp. to every vector on the plane right? Let $\displaystyle \vec{r}, \vec{r_0}, \vec{r_1} -\vec

{r_0} $ be vectors on the plane.

Then $\displaystyle n \cdot (\vec{r}-\vec{r_0}) = 0 $.

Then shouldnt $\displaystyle n \cdot \vec{r_0} = n \cdot \vec{r_1} = 0 $?