Question

X=4i-2j

Y=i+5j

determine; i. the magnitude of x+y

ii. x-4y

the unit vector _y^{^}

Answer 1

Given:

$x=4i-2j$

$y=i+5j$

(i)

$$|x+y|=|4i-2j+i+5j|\\=|5i+3j|=\sqrt{5^2+3^2}=\sqrt{34}=5.8$$

(ii)

$$|x-4y|=|4i-2j-4i-20j|\\=|-22j|=22$$