Chapter 12.1, Problem 103E

(a)

To determine

To show: The least distance from the point $Q$ to the plane $ax+by+cz=d$ is $\frac{\left|\overrightarrow{PQ}\cdot n\right|}{\left|n\right|}$.

(b)

To determine

To find: The least distance from the point $\left(1,2,4\right)$ to the plane $2x-y+3z=1$.