A={2,1,3},b={1,4,3}.Найти |a+b|^2
A+b = {2+1; 1+4; 3+3} = {3; 5; 6} |a+b| = √(3^2 + 5^2 + 6^2) = √(9 + 25 + 36) = √70 |a+b|^2 = 70