merge subplot matplotlib
import numpy as np
import matplotlib.pyplot as plt
x = np.arange(0, 7, 0.01)
plt.subplot(2, 1, 1)
plt.plot(x, np.sin(x))
plt.subplot(2, 2, 3)
plt.plot(x, np.cos(x))
plt.subplot(2, 2, 4)
plt.plot(x, np.sin(x)*np.cos(x))