O1 2 Points Let A: l'l'll HHH 1 1 U Show that all leading principle minors of A are nonnegative. but A is not positive semi definite. {Hint: Show that A is not positive semi-definite by computing its eigenvalues.) Q2 2 Points Find a symmetric matrix which represents the quadratic form f(x, y, z) = x' + 4xy - xz + 6yz - 32.Q3 2 Points Consider the quadratic form f(1, 2, x3) = x1+ x2 + 5x3 + 2ax142 -2x1x3 + 4x2x3 = x Qx (A) What is the matrix Q? (B) Find the values of the parameter a for which this quadratic form is positive definite