Let \(n\) be a positive integer and \(x\) be a positive real. Prove that \[\dfrac{n(nx+1)}{x+1} \le \dfrac{(x+1)^{2n}-1}{(x+1)^2-1}\] and find equality case.

Hint (zoom in to read):

\(\tiny _{\text{The inequality is still true even when loosening the restriction of }x\text{ to }x > -1}\)

Bigger hint: link

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TopNewestx>0 not x>=0 because if x=0 you get a non defined operation: 0/0 Nice problem ;) – Carlos David Nexans · 2 years, 3 months ago

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Has anyone solved this problem yet? I have a pretty big hint as my second hint... – Daniel Liu · 2 years, 3 months ago

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– Samuraiwarm Tsunayoshi · 1 year, 12 months ago

Nah I ended up at \(1 \geq 2\) and exploded the universe.Log in to reply

Final hint: multiply \(x+1\) on both sides. Does the format of the resulting product resemble a known formula? – Daniel Liu · 2 years, 2 months ago

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