Verify the first special case of the chain rule for the composition f o c in each of the cases. (a) f(x, y) .xy, c(t) (e cos(t)) (f o c) (t) '(cos (t) sin t (f o c) (t) (e e Y 2t 2t (f o (c) (t) n e (d) f(x, y) x exp(x y c (t) (t, -t) (f o c) (t) 4t 1