c = S(2) / 10
p1 = plot(cos(x) * exp(-c * x), (x, 0, 10), "f(x)", title="plot 1")
p2 = plot(
    (exp(-c * x), "upper limit"),
    (-exp(-c * x), "lower limit"), (x, 0, 10), {"linestyle": "--"},
    title="plot 2", xlabel="xx", ylabel="yy")