Figure_2.py

import matplotlib.pyplot as plt
import numpy as np

plt.style.use("seaborn")

x = np.linspace(0, 2*np.pi, 100)
sin = np.sin(x)
cos = np.cos(x)
plt.plot(x, sin, "C0--", label="sin(x)")
plt.plot(x, cos, "C1:", label="cos(x)")

pi_multiples = np.array([0, 0.5, 1, 1.5, 2]) * np.pi
sin_points = np.sin(pi_multiples)
cos_points = np.cos(pi_multiples)
plt.plot(pi_multiples, sin_points, "C0o")
plt.plot(pi_multiples, cos_points, "C1o")

plt.title("Trigonometric functions")
plt.xlabel("x (radians)")
plt.xticks(np.linspace(0, 2*np.pi, 5))
plt.legend()
plt.axis("scaled")

plt.show()