In the theory of relativity the lorentz contraction formula

In the theory of relativity, the Lorentz contraction formula L=L0√1−v2/c2 expresses the length L of an object as a function of its velocity v with respect to an observer, where L0 is the length of the object at rest and c is the speed of light.

a. Find lim v→c-L and interpret the result.
b. Why is a left-hand limit necessary?