If `bar(a) = 2hat(i) + hat(j) - 3hat(k)` and `bar(b) = hat(i) - 2hat(j) + hat(k)`, find a vector of magnitude 5 perpendicular to both `bar(a)` and `bar(b)`.

Answer

`pm (hat(i) + hat(j) + hat(k))/(sqrt(3))`