Menu Close

Let-a-b-c-gt-0-and-a-b-c-3-Prove-that-ab-ab-1-bc-bc-1-ca-ca-1-1-ab-1-1-bc-1-1-ca-1-abc-Found-by-WolframAlpha-and-inspire




Question Number 144742 by loveineq last updated on 28/Jun/21
Let a,b,c>0 and a+b+c = 3. Prove that                        ((((ab)/(ab+1))+((bc)/(bc+1))+((ca)/(ca+1)))/((1/(ab+1))+(1/(bc+1))+(1/(ca+1)))) ≥ abc  (Found by WolframAlpha and                  inspired by my old problem)
$$\mathrm{Let}\:{a},{b},{c}>\mathrm{0}\:\mathrm{and}\:{a}+{b}+{c}\:=\:\mathrm{3}.\:\mathrm{Prove}\:\mathrm{that}\:\: \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\frac{\frac{{ab}}{{ab}+\mathrm{1}}+\frac{{bc}}{{bc}+\mathrm{1}}+\frac{{ca}}{{ca}+\mathrm{1}}}{\frac{\mathrm{1}}{{ab}+\mathrm{1}}+\frac{\mathrm{1}}{{bc}+\mathrm{1}}+\frac{\mathrm{1}}{{ca}+\mathrm{1}}}\:\geqslant\:{abc} \\ $$$$\left(\mathrm{Found}\:\mathrm{by}\:\mathrm{WolframAlpha}\:\mathrm{and}\:\right. \\ $$$$\left.\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\mathrm{inspired}\:\mathrm{by}\:\mathrm{my}\:\mathrm{old}\:\mathrm{problem}\right) \\ $$

Leave a Reply

Your email address will not be published. Required fields are marked *