1. Write an implicit equation for the 2D line through points (x0, y0) and (x1, y1) using a 2D determinant.
2. Show that if the columns of a matrix are orthonormal, then so are the rows.
3. Prove the properties of matrix determinants stated in Equations (5.5)-(5.7).
4. Show that the eigenvalues of a diagonal matrix are its diagonal elements