Square of distance between two points for JEE

Formula

\(PQ^2=(x_2-x_1)^2+(y_2-y_1)^2+(z_2-z_1)^2\)

Variables: \(P(x_1,y_1,z_1),\ Q(x_2,y_2,z_2)\).

Avoiding square roots in equality/comparison problems, proving perpendicularity or midpoint relations.