Question

What does it mean for a column vector, \[{\bf V}\] to span R^n?
Does it mean that there are n real entries in the column vector?

Answer 1

R^n usually denotes dimensions; R^3 is 3 dimensions; R^2 is 2 dimensions

Answer 2

span(V) is the set of all linear combinations of vectors in V. If you just have one vector it can only span R. you need 2 linearly independent vectors to span R^2 and so on.