Let , be the separation vector from a fixed point (x', y, z') to the point (x, y, z), and let be its length.

Let π, be the separation vector from a fixed point (x', y’, z') to the point (x, y, z), and let π be its length. Show that

(a) ∆ (π2) = 2 π

(b) ∆ (1/π) = – π/π2.

(c) What is the general formula for ∆(πn)?