import matplotlib.pyplot as plt
import numpy as np

fig, ax = plt.subplots(1, 1, figsize=(4,4), dpi=120,)

ax.set_xlim(-1,1); ax.set_ylim(-1,1)

n = 7
x = np.arange(n+1)/n * 2*np.pi
ax.plot(np.sin(x), np.cos(x))
ax.set_title("n=7")