[geometry] vectors [calc III]

I was struggling on a problem in my homework the other day. I don't remember exactly what the problem was, but it had to do with finding the (unit) normal (and binormal) vector from a point on a line in 3 dimensional space.

I couldn't figure out how to get a normal vector from a single vector (the one defining the line). Is there a simple way to do this that I am overlooking?

It's like the 5th week of classes?  You should be doing partial derivatives by now.