Friday, 5 February 2016

real analysis - limlimitsxto0+f(x) and limlimitsxto0+g(x) do not exist, limlimitsxto0+f(x)g(x) does



I am looking for functions f,g:(0,+)(0,+) such that limx0+f(x) and limx0+g(x) do not exist, however, limx0+f(x)g(x) does. So far, I have only encountered two functions for which the one-sided limit doesn't exist: sin1x and cos1x. This doesn't seem to be what I'm looking for. I would appreciate any hints.


Answer



For example: f(x)={2ifx rational1/2ifx irrational,g(x)={2ifx irrational1/2ifx rational.


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