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jalvarado
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Homework Statement
Define [itex]G[/itex] as follows:
[itex]G(x) = \left\{
\begin{array}{c l}
x, & \mbox{if } x \mbox{ is irrational} \\
\sqrt{\frac{1+p^2}{1+q^2}}, & \mbox{if } x = \frac{p}{q} \mbox{where } gcd(p,q) = 1
\end{array}
\right.[/itex]
Show that [itex]G[/itex] is discontinuous at each negative number and also at each nonnegative rational number, but is continuous at each positive irrational number.
Homework Equations
[itex]\lim_{x \rightarrow a} f(x) = f(a)[/itex]
The Attempt at a Solution
I found this question in an old calculus book at the end of the limits and continuity section.
I tried the approach using [itex]\lim_{x \rightarrow a} G(x) = G(a)[/itex] and trying the different cases for [itex]a[/itex] and it makes sense intuitively but I'm thinking and epsilon-delta approach is what is needed here. Any help?
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