Question

найдите квадрат длины вектора a+b. a(-4;-8) b (-11;-3)

Answer 1

$<var>mathbf{a} + mathbf{b}</var> = [-4 + (-11); -8 + (-3)] = [-15; -11]$

 

$<var>left| mathbf{a} + mathbf{b} right|^2 = left(mathbf{a + b}right) cdot left(mathbf{a + b}right)</var> =$

$<var>= (-15)^2 + (-11)^2 </var>= 225 + 121 = 346$