Limit of x to the x/Proof 1

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Theorem

Let $f: \R_{>0} \to \R$ be defined as:

$\forall x \in \R_{>0}: \map f x = x^x$


Then:

$\ds \lim_{x \mathop \to 0^+} x^x = 1$


Proof

\(\ds \lim_{x \mathop \to 0^+} x^x\) \(=\) \(\ds \lim_{x \mathop \to 0^+} \map \exp {x \ln x}\) Definition 1 of Power (Algebra)
\(\ds \) \(=\) \(\ds \map \exp {\lim_{x \mathop \to 0^+} x \ln x}\) Exponential Function is Continuous
\(\ds \) \(=\) \(\ds \map \exp {\lim_{x \mathop \to 0^+} \frac {\ln x} {\frac 1 x} }\)
\(\ds \) \(=\) \(\ds \map \exp {\lim_{x \mathop \to 0^+} \frac {\frac 1 x} {\frac {-1} {x^2} } }\) L'Hôpital's Rule
\(\ds \) \(=\) \(\ds \map \exp {\lim_{x \mathop \to 0^+} \frac {-x^2} x}\)
\(\ds \) \(=\) \(\ds \exp 0\)
\(\ds \) \(=\) \(\ds 1\) Exponential of Zero

$\blacksquare$