k/pluginfile.php/2696010/mod_resource/content/5/CW2.pdf + Question 4 [12 marks] Consider the following optimisation problem min f(x, y) =xty-x2 subject to r +y - 1 x 2 0, y > 0. a) Find a critical point of the Lagrangian. b) Find a better solution to the problem above than the critical point of the Lagrangian calculated in a). c) What sufficient condition for the optimality of the Lagrangian solution is violated by the