極座標方程： $\rho =a(1-\sin \theta )$

極座標畫圖：

%matplotlib inline
import matplotlib.pyplot as plt
import numpy as np

theta = np.linspace(0.0, 2 * np.pi, 1000)
a = 5
rho = a * (1 - np.sin(theta))
plt.subplot(polar=True)
plt.plot(theta, rho, c = 'r')
plt.show()
 

直角座標畫圖：
python程式：

%matplotlib inline
import matplotlib.pyplot as plt
import numpy as np

theta = np.linspace(0.5*np.pi, 1.5*np.pi, 1000)
sintheta = np.sin(theta)
a = 1
y = a * sintheta * (1 - sintheta)
x = np.sqrt((1 - sintheta) ** 2 - y ** 2)
x1 = np.hstack((x,-x[::-1]))  #x[::-1]意思是反轉x
y1 = np.
 
hstack((y,y[::-1]))
plt.plot(x1, y1, c = 'r')
plt.show()