Verify the first special case of the chain rule for the composition foc in each of the cases. (a) f(x, y) = xy, c(t) = (et, cos(t)) (fo c)'(t) = (b) f(x, y) = exy, c(t) = (5+2, +3) (foc)'(t) = (c) f(x, y) = (x2 + y2) log(x2 + y2), c(t) = (et, e-t) + (foc)'(t) = (d) f(x, y) = x exp(x2 + y2), c(t) = (t, -t) (fo c)'(t) =