def show_plot(t_array, th_array):
    """ Display theta vs t plot. """
    th_mean = gv.mean(th_array)
    th_sdev = gv.sdev(th_array)
    thp = th_mean + th_sdev
    thm = th_mean - th_sdev
    plt.fill_between(t_array, thp, thm, color='0.8')
    plt.plot(t_array, th_mean, linewidth=0.5)
    plt.xlabel('$t$')
    plt.ylabel(r'$\theta(t)$')
    plt.savefig('pendulum.pdf', bbox_inches='tight')
    plt.show()
Display theta vs t plot.