Question

дано вектор a {5;-1;2} вектор b {3;2;-4} найти |a-2b|

Answer 1

a={5;-1;2}
b={3;2;-4}
a-2b={5-2*3;-1-2*2;2-2*(-4)}={-1;-5;10}
$|a-2b|= sqrt{(-1)^2+(-5)^2+10^2} = sqrt{126} =3 sqrt{14}$