//page 143
clear;
close;
clc;
x1=[2;2;-1];
disp(x1,'x1=');
x2=[-1;2;2];
disp(x2,'x2=');
disp(x1'*x2,'x1''*x2=');
disp('Therefore,X1 is orthogonal to x2 .Both have length of sqrt(14).')