Given two points X1, X2 ( R" we define the Euclidean distance between them by a function PE : R x R _ R defined as: d PE(X1, X2) = _(X1,K - X2,k)2 k=1 Similarly, we define the taxicab distance pr : R" x R* => R by: d PT(X1, X2) = X1,k - X2,k k=1 Prove that the metric space (RR" , pE) is complete iff the metric space (R" , pr) is complete