N less than M to the N

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Theorem

$\forall m, n \in \Z_+: m > 1 \implies n < m^n$


Proof

\(\displaystyle \) \(\displaystyle n\) \(=\) \(\displaystyle 1 + 1 + \cdots \left({n}\right) \cdots + 1\) \(\displaystyle \)                    
\(\displaystyle \) \(\displaystyle \) \(<\) \(\displaystyle 1 + m + m^2 + \cdots + m^{n + 1}\) \(\displaystyle \)          (as $m > 1$)          
\(\displaystyle \) \(\displaystyle \) \(=\) \(\displaystyle \frac {m^n - 1} {m - 1}\) \(\displaystyle \)          Sum of Geometric Progression          
\(\displaystyle \) \(\displaystyle \) \(\le\) \(\displaystyle m^n - 1\) \(\displaystyle \)          (as $m-1 \ge 1$)          
\(\displaystyle \) \(\displaystyle \) \(<\) \(\displaystyle m^n\) \(\displaystyle \)                    

$\blacksquare$


Source

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