5. What is special about the Newton-Raphson method of solving min {f(x)} TERn when f(x) is a quadratic function f (a) = -xQx+ cix with Q a positive definite matrix? Justify your answer. 6. Consider the steepest descent method to solving min {f (x) } CERn when f(x) = Ex Qx + cix starting from x) E R". Show that if the step size a () = 1, then x) satisfies the first order necessary conditions only if ( I - Q) (Qx0) + c) = 0