using matplotlib to draw pic of function of cos and sin

```import numpy as np
import math 
import matplotlib.pyplot as plt
x=np.linspace(0,2*math.pi)
plt.plot(x,np.sin(x),label=r"$\sin(x)$")
plt.plot(x,np.cos(x),"ro",label=r"$\cos(x)$")
plt.title(r"Two plots in a graph")
plt.legend()