题型:判断题 对于函数f(x)=1x(x>0)定义域中任意x1,x2(x1≠x2)有如下结论:①f(x1+x2)=f(x1)+f(x2); ②f(x1x2)=f(x1)f(x2); ③f(x1)-f( x2)x1-x2>0; ④f(x1+x22)<f(x1)+f( x2)2.上述结论中正确结论的序号是______. 查看答案