from sympy import Eq
import matplotlib.pyplot as plt
import numpy as np

def plot_circle(x = 0, y = 0, radius = 1, start = 0, end = 2 * np.pi, **kwargs):
    #plt.gca().set_aspect('equal', adjustable='box')
    steps = 100
    angles = np.linspace( start, end, steps )
    x = radius * np.cos(angles) + x
    y = radius * np.sin(angles) + y
    plt.plot(x, y, **kwargs)

plt.arrow(0, 1, 1, 0, width = 0.02, color = 'blue')
plot_circle()
plt.text(0.5, 1.1, r'$\vec{v}$', fontsize = 14)
# plt.arrow(0, 1, 0, -0.5, width = 0.03, length_includes_head = True)
plt.plot([0, 0, 0], [1, 0.5, 0], 'r')
plt.plot(0, 0, 'ro')
plt.plot(0, 0.5, 'rv', markersize = 10)
plot_circle(start = np.pi/6, end = np.pi/2)

plt.gca().set_aspect('equal', adjustable='box')