plt.figure(figsize = (11,8)) #specify figure size as 7 x 5 inches
#for default size, type plt.figure()
plt.xlabel(r"$\theta$ [degrees]", fontsize = 18) #label axis (using LaTeX commands)
plt.ylabel(r"$V_{pd}$ [volts]", fontsize = 18) #use 18 point font for label text
# plot the data as before in blue
plt.errorbar(angle, V_pd,
xerr=None, yerr=V_pd_error,
linestyle = 'none',
color = 'blue',
capsize = 3, capthick = 1, label = "data")
#create curve showing fit to data
angle_fit = np.linspace(0, 360, 180)
theta_fit = angle_fit * np.pi / 180
V_pd_fit = polarization_model(theta_fit, fit[0], fit[1], fit[2])
#plot the curve fit in red
plt.errorbar(angle_fit, V_pd_fit, xerr = None, yerr = None, color = 'red', label = 'fit' )
plt.xlim(-15, 375)
plt.ylim(-2.5, 40)
plt.xticks([0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360],
('0', '', '', 90, '', '', 180, '', '', 270, '', '', 360))
plt.legend(loc = 'best')
plt.show()