笛卡儿是法国著名的数学家。有一次,他生病卧床还在反复思考一个问题:几何图形是直观的,代数方程则比较抽象,能不能用几何图形来表示方程呢?这里,关键是如何把组成几何的图形的点和满足方程的每一组“数”挂上钩。他拼命琢磨,通过什么样的办法才能把“点”和“数”联系起来呢。突然,他看见屋顶角上的一只蜘蛛拉着丝垂了下来,一会儿,蜘蛛又顺着丝爬上去,在上边左右拉丝。蜘蛛的“表演” Descartes is a famous French mathematician. Once, his bedridden illness is still thinking about one question: Geometry is intuitive, algebraic equations are more abstract, can we use the geometry to represent the equation? Here, the key is how to form the geometric point of the graph and meet the equation Each group “number ” hook up. He tried hard to figure out what way we can associate “dot” with “number”. Suddenly, he saw a spider hanging down at the corner of the roof, and for a moment, the spider climbed up the wire again and pulled the wire from top to bottom. Spider’s “show”