Let f be a function admitting continuous second partial derivatives, about which it is known that: Vf(:1t, y) (253:3 1:312, 4y3 3523/ l 163/2 + 16y) frm: 75:62 3/2 fyy 12y2 3:9 + 32y + 16 3! fig = 2:vy Consider the critical point (a, b) with positive xcoordinate, such that this critical point generates a saddle point. Determine the value of b