除了教材给出的双曲线性质外,双曲线还有其它性质值得探索。笔者给出几个结论,会给读者解答客观性命题带来很大方便。1·过点P(m,n)作直线l与双曲线xa22-by22=1仅【例1】过P(4,33)点作直线l与双曲线x42-y29=1仅有一个公共点,这样的l能作条.解:经检验,P点在双曲线上,故l有3条.2 In addition to the hyperbolic properties given in the textbook, there are other properties of the hyperbolic curve that are worth exploring. The author gives a few conclusions that will give readers a great deal of convenience in answering the objectivity proposition. 1) Overpoint P(m,n) for line l and hyperbola for xa22-by22=1 only [Example 1] P(4,33) point for line l and hyperbola x42-y29=1 have only one common point This kind of l can be used as a strip. Solution: After testing, P point is on the hyperbola, so l has 3 .2