Prove $$\ln(n) \lt n \;\;(n\in \mathbb N) $$
Using only the rule $$\log(x^y) = y\log(x) $$
I tried using any of the known Inequalities am-gm, power mean, titu's lemma, holder's,... but I seem I can't go anywhere near required.
Any hint?
$\mathbf {Edit} $
It was simpler than I thought, it's done with Bernoulli's Inequality.
$$e^n\gt 2^n = (1+1)^n \ge 1+n \gt n$$
$$\ln(e^n) \gt \ln(n)$$
$$\ln(n) \lt n$$
Answer
Your inequality could be generalized as $$\ln x \leq x-1, x>0$$ To prove it, you perhaps have to use calculus, not just elementary mathematics.Notice that, for $f(x)=\ln x-x+1,(x>0)$, $$f'(x)=\frac{1}{x}-1.$$ Thus, $f'(x)>0,$ when $0
But if you have known Bernoulli's inequality, there indeed exists an elementary proof.
Since
$$(1+x)^n \geq 1+nx,(x \geq -1, n\in \mathbb{N_+}).$$
Let $x=e-1$. Then $$e^n \geq 1+n(e-1)=1+ne-n>n.$$
It follows that $$n>\ln n.$$
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