
Circulant Determinant
So in class we solved for the circulant determinant by multiplying the circulant with the Vondermonde's determinant. Point is I have no idea why she did this. Can some one explain? I can give the example from class but its supper long since she did so many steps.

We do need more details. If you simply multiply a circulant matrix by a Vandermonde determinant (which is a scalar), then you get another matrix (so not a circular determinant).
What is the entries of your circulant? The entries of the Vandermonde matrix? What is the context?