import matplotlib.pyplot as plt
 
plt.ion()
 
# Center of the circle
a=1


# Define radius
r = 3

 
# Create the circles using plt.Circle
fig, ax = plt.subplots()
circle = plt.Circle((a, 0), r, color='red',alpha=0.5)


# Add the circle to the plot
ax.add_artist(circle)


# Set equal scaling
ax.set_aspect('equal')

 
# Set plot limits
plt.xlim(-3, 5)
plt.ylim(-4, 4)