import numpy as np
import matplotlib.pyplot as plt

def f(t):
    return np.exp(-t) * np.cos(2*np.pi*t)

t1 = np.arange(0.0, 5.0, 0.1)
t2 = np.arange(0.0, 5.0, 0.02)

fig, axs = plt.subplots(2, 2)

axs[0, 0].plot(t1, f(t1), "b.")
axs[0, 1].plot(t2, f(t2), "k")
axs[1, 0].plot(t2, np.cos(2*np.pi*t2), "r--")
axs[1, 1].plot(t2, np.cos(2*np.pi*t2), "g.")

plt.show()