u=<3,-2,1> v=<2,-4,-3> and w=<-1,2,2>
Determine a unit vector perpendicular to the plane containing v and w.
I dont understand how to find it perpendicular containing v and w???
Not sure why you need the vector u. Basically, when you take the cross product between v and w, the resultant vector will be orthogonal to v and w - indicating that it'll also be orthogonal to the plane created by v and w as well.
So take the cross product between w and v to get your resultant vector, let's call it s. Now, to find the unit vector: $\displaystyle \hat{s} = \frac{\vec{s}}{||\vec{s}||}$