#笛卡尔心形线，r=a(1-sinθ）
import math
import matplotlib.pyplot as plt
import numpy as np
r=[]
angle=[]
for i in np.arange(0,101):
    x=2*math.pi/100*i
    angle.append(x)
    r.append(1-math.sin(x))
fig=plt.figure()
ax1=fig.add_axes([0.1,0.1,0.8,0.8],projection='polar')
ax1.set_rgrids(np.arange(2,2,1))
ax1.set_rlabel_position(90)
ax1.plot(angle,r,'-r',linewidth=2.5)#lw=2.5
plt.savefig('heart.png',dpi=600)
plt.show()