有理函数y=f(x)/g(x)的值域

The Value Fields of Rational Function y=f(x)/g(x)

从一道例题的错误证法出发 ,系统地讨论了有理函数值域的求法 。

Through analysis on a false proving of anexample,I stupy the method to gain the value field ofthe rational function,finding out a Principal withpractical value.