Question

What is the unit vector perpendicular to the vectors 2i+2j-k and 6i -3j +2k. there are 4 options and the ans is i-10j-18k the whole divided by 5 root 17.
[but while calculating iam not getting the dot product as 0] why

Answer 1

you have not done dot product correctly
$2 - 20 + 18 = 0$
and
$6 + 30 - 36 = 0$