Rotation of ellipsoid using matrix

I have ellipse matrix A^-1 and vector b by solving cvx problem. A^-1 eigenvalues are major and minor axis. But still can’t find the rotation angle of ellipsoid. If you can help it would be nice!

[James Tursa]

Do you have the eigenvectors? Can't you get the desired angle from those?

[Mirzobek Malikov]

i have eigenvectors. but i don’t know how to get desired angle

Answer 1

[Matt J]

You just compute the angle between one of the eigenvectors with the x or y axis.