1 import numpy as np
 2 import matplotlib.pyplot as plt
 3 from matplotlib.ticker import EngFormatter
 4 
 5 t = np.arange(2.0, 3.05, 0.05)
 6 s = np.sin(np.pi * t)
 7 c = np.cos(np.pi * t)
 8 fig, ax = plt.subplots()
 9 formatter = EngFormatter(unit='$\pi$', places=1)
10 ax.xaxis.set_major_formatter(formatter)
11 l1, l2 = ax.plot(t, s, t, c)
12 ax.grid(True)
13 fig.legend((l1, l2), ('sin', 'cos'))
14 plt.savefig("cs.png")