一、反函数的存在性在定义域上单调的函数一定有反函数,但在定义域上非单调函数未必没有反函数,或者说有反函数的原函数不一定是单调函数．如函数y=1/x(x≠0)有反函数,但其在定义域上不是单调函数．二、互为反函数的函数的图像交点情况 First, the existence of inverse function In the definition domain, the monotonous function must have an inverse function, but in the definition domain, the non-monotonic function may not have no inverse function, or the original function with an inverse function is not necessarily a monotone function. If the function y=1/x(x≠0) has an inverse function, but it is not a monotonic function in the definition domain. Second, the image intersection point of the inverse function function