历年来反比例函数问题是各地中考数学的重点与热点,其中有一类反比例函数考题可采用“设而不求”的方法进行求解.一般是先设出双曲线上一点的横坐标作为辅助元,然后借助辅助元及k联系起已知与未知的关系,列式或方程,最后通过约分约去辅助元从而获解.运用这种方法会收到化繁为简、化难为易的效果. Over the years, the problem of inverse proportion function is the focus and hot spot of the mathematics examinations in different places, among which there is a class of inverse proportion function test questions that can be solved by using “instead of ” .It is generally necessary to first set the abscissa on the hyperbolic point as the auxiliary element , And then use the auxiliary element and k to link the known and unknown relations, columns or equations, and finally get the solution by about points to auxiliary elements. Using this method will receive the effect of simplification and simplification. .