(9) Show that each of the following functions is convex or strictly convex.(a)f(x, y) = 5x2+ 2xy+y2-x+ 2y+ 3(b)f(x, y) =(x+ 2y+ 1)8-log((xy)2),if 0< x,0< y,+∞,otherwise.(c)f(x, y) = 4e3x-y+ 5ex2+y2(d)f(x, y) =x+2x+ 2y+4y,if 0< x,0< y,+∞,otherwise.
(b) The convexity offfollows from that of-logμforμ >0.(10) Compute the global minimizers of the functions given in the previous problem if they exist.