Love won\'t obey our expectation.Its mystery is pure and absolute.This is a story about a great mathematician In 1956, 52-year-old Descartes met 18-year-old Swedish prince Christine on a street of Stockholm.At that time, Descartes lived a begging life.But he never asks for paers-by, he just silently bowed his head, drawing on the paper, and immersed in his math world.In a quiet afternoon，Descartes as usual sitting in the street, studied math problems in the sun.Suddenly, someone came to his side, \"what are you doing?\" Looked away, Descartes see a young lovely face, a pair of limpid eyes that like the blue of the lake, looking forward to his response.She is the little prince of Sweden, Christine.She squatted down body, took the math books and draft paper of Descartes, and talked with him.At dusk, the girl said goodbye to him, and Descartes gradually forgot it.However, a few days later, he received a notice; the king hired him to do the little prince\'s math teacher.Waiting in the lounge, he heard the sound of laughter from the distance.Turned around, he saw the casual girl he had met in the street.From then on, he became her math teacher.
Unfortunately, the Black Plague arrived in Europe.Shortly after infirm Descartes returned to France, and severed disease.He mied Christine very much and wrote to her every day.However, these letters were stopped by the king; the prince had not received any news of him.This situation continued until the thirteenth letter.But after this letter, Descartes left the world forever.On his last letter he didn\'t write a word, only one equation: R = a (1 - sine theta).How to look not understand and the king could not bear to look at his beloved daughter unhappy every day, he gave the letter to her.Christine immediately understood the intention of her lover, found a pen and paper, and drew out the equation.A heart shaped pattern appeared in sight; and tears were running down her face.This curve is the famous \"heart line\".
