Answer
$3$
$-i + 5j$
$ i + j$
$ 6j$
$2i + 5j$
Work Step by Step
This question asks to find $|u|, u + v, u - v, 2u, 3u-2v$
Given $u = 3j$ and $v = -i + 2j$
$u = <0, 3>$ and $v = $
$|u| = \sqrt {0^2 + 3^2} = 3$
$u + v = <0 + (-1), 3 + 2> = = -i + 5j$
$u - v = <0 - (-1), 3 - 2> = <1, 1> = i + j$
$2u = <2(0), 2(3)> = <0, 6> = 6j$
$3u - 2v = <3(0) - 2(-1), 3(3) - 2(2)> = <2, 5> = 2i + 5j$
