Thanks to all that can help. I'm given the matrix A= [-3, square root of 3] [ negative square root of 3, 1]. The question asks you to find the diagonalized matirx.

I find the determinant to be A(A+2) where lamba=A so A1=0, A2=-2. Is this right? If it is what is my P matrix? I have only one eigenvector from A2=-2 to be [square root 3][1] and with that you can't get a P inverse. Which is needed for the formula D=P^1AP