import numpy as np
import matplotlib.pyplot as plt

x = [1,2,3,4,5]
y =  [0.873,1.14,1.246,1.289,1.305]
plt.plot(x,y,'ro')
plt.axis([0,5,0,3])

z = np.polyfit(x,y,1)
p = np.poly1d(z)
plt.plot(x,y,'ro',x,p(x),'r--')
plt.ylabel("Volts")
plt.xlabel("Tau")
plt.title("Capacitor Charging")
plt.show()