1, take a point as the center, take any radius, and draw a circle symmetrically with this center;
2. Still take this point as the center, and then continue to draw a circle symmetrically with a larger distance as the radius; And so on.
Draw the heart line as shown in the following figure:
Extended data:
1, the basic properties of the centerline:
When a= 1, the circumference of the cardiac line is 8 and the closed area is 3π/2.
Heart line is also a kind of line.
The figure in the middle of the Mandelbrot set is a heart-shaped line.
The English name "Cardioid" of the cardiac line was published by de Castillon in the Journal of Philosophy of the Royal Society in 174 1. It means "like a heart".
2, the history of the heart line
Christine was a princess in Sweden in the17th century. She is beautiful, kind and intelligent, and especially likes math. One day, she put on casual clothes and went outside the palace. On the way, she saw many beggars, one of whom was very special. He didn't take the initiative to ask passers-by for charity, but quietly squatted on the ground and concentrated on studying math problems.
The man didn't know that the lady standing in front of him was the princess, but he was surprised by the mathematical talent revealed in the lady's words, so he was happy to talk to Christine. Princess Christine realized that he was originally a mathematician, but unfortunately, for some reason, he was frustrated in doing mathematics in France and was down and out, and finally he wandered to Sweden.
So Princess Christine invited mathematicians to the palace to be her math teacher, and they discussed math problems together and talked about everything. For a long time, they were immersed in the world of mathematics and love, and they were very happy.
But Christine's father knows her daughter's love. The stubborn king doesn't care about mathematics and mathematicians at all. He felt that the French boy was not good enough for his daughter, so he forcibly separated them, dispersed the mathematicians from China, and never allowed him to set foot in his own country again. He also kept all the letters he wrote to the princess afterwards. ...
I haven't heard from my lover since she left, which makes Christine reticent and doesn't like talking to anyone anymore … because there is only one person in the world who can communicate and discuss with her!
When the man returned to France, he was infected with the Black Death and was dying. Before he died, he sent his thirteenth and last letter to his princess, his lover, Christine. This time the king opened the letter, but he couldn't understand what he was writing. Show it to ministers. Ministers can't understand it. I invited many mathematicians to look at it, but I still can't understand it.
Finally, the king had no choice but to return the letter to Christine. Christine opened the last letter left by her lover and found that there was only one simple mathematical formula: r = a( 1-sinθ).
References:
Heart line? Baidu baike