2nd Order Diff Eqn. (complex roots)

1. The problem statement, all variables and given/known data
Prove that if y1 and y2 have maxima or minima at the same point in I, then they cannot be a fundamental set of solutions on that interval.


2. Relevant equations

Do I take the wronskian (determinant of y1, y1', y2, y2')? What would that tell me?

3. The attempt at a solution

 

The wronskian is a determinant that tells us whether a set of functions is linearly independent or not right? How does that relate to maxima/minima?