Question

Find a unit vector perpendicular to each of the vectors `( -> a+ -> b)` and `( -> a- -> b)` , where ` -> a= hat i+ hat j+ hat k , -> b= hat i+2 hat j+3 hat k` .

Answer 1

Correct Answer - `pm(5(-hat(i)+2 hat(j) - hat(k)))/sqrt(6)`
`(pm 5[(vec(a) + vec(b)) xx ( vec(a) -vec(b))])/(|(vec(a)+ vec(b))xx(vec(a) - vec(b))|)`