摘要
The French mathematician Rene Descartes (1596-1650) published, in 1637, his Discours de la methode (Discussions on the Method)-of finding scientific truth by good reasoning, that is. In a hundred-page appendix to this book Descartes combined algebra and geometry. He pointed out that if one drew two perpendicular straight lines, marked the intersection 0, and laid off units on each line, positive numbers to the right and up, negative numbers to the left and down, then every point in the plane could be pre...
