Is there a Continuous Function f:R-->R Discontinuous at All Other Numbers?

nikolany
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Is there a function f:R-->R that is continuous at π and discontinuous at all other numbers?

Thx

 
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Consider the function f(x)=0 for x irrational and f(x)=x for x rational. Where is that continuous? Can you modify that for your purposes?
 
Dick said:
Consider the function f(x)=0 for x irrational and f(x)=x for x rational. Where is that continuous? Can you modify that for your purposes?

So f(x)=(x-π)^18 for x rational and 0 otherwise should work I think!

Thank you very much
 
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