import numpy as np
import matplotlib.pyplot as plt

v = np.linspace(0, 20, 40)
c = np.cos(v)
s = np.sin(v)

plt.close('all')
plt.figure(1, figsize=(12, 9))

plt.subplot(2, 1, 1)
plt.plot(v, c, 'r*-', label='c = cos(v)')
plt.legend()
plt.grid()
plt.xlabel('v [rad]')

plt.subplot(2, 1, 2)
plt.plot(v, s, 'bo-', label='s = sin(v)')
plt.legend()
plt.grid()
plt.xlabel('v [rad]')

plt.savefig('subplott.pdf')
plt.show()