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Category: Algebra

lim-n-sin-2-pi-n-2-n-

Question Number 145531 by mathdanisur last updated on 05/Jul/21 $$\underset{{n}\rightarrow\infty} {{lim}sin}^{\mathrm{2}} \pi\:\sqrt{{n}^{\mathrm{2}} +{n}}\:=\:? \\ $$ Answered by Olaf_Thorendsen last updated on 05/Jul/21 $$\mathrm{sin}^{\mathrm{2}} \pi\sqrt{{n}^{\mathrm{2}} +{n}}\:=\:\mathrm{sin}^{\mathrm{2}}…

Question-145525

Question Number 145525 by mathdanisur last updated on 05/Jul/21 Answered by Olaf_Thorendsen last updated on 05/Jul/21 $${f}\left({x}+\mathrm{2}\right)+\mathrm{10}{f}\left({x}\right)\:=\:\mathrm{7}{f}\left({x}+\mathrm{1}\right) \\ $$$${f}\left({x}+\mathrm{2}\right)−\mathrm{7}{f}\left({x}+\mathrm{1}\right)+\mathrm{10}{f}\left({x}\right)\:=\:\mathrm{0} \\ $$$${r}^{\mathrm{2}} −\mathrm{7}{r}+\mathrm{10}\:=\:\mathrm{0} \\ $$$$\left({r}−\mathrm{2}\right)\left({r}−\mathrm{5}\right)\:=\:\mathrm{0} \\…

1-2-a-b-a-b-min-

Question Number 145530 by mathdanisur last updated on 05/Jul/21 $$\left(\frac{\mathrm{1}}{\mathrm{2}}\:+\:\frac{\mid{a}\mid\:+\:\mid{b}\mid}{\mid{a}\:+\:{b}\mid}\right)_{\boldsymbol{{min}}} =\:? \\ $$ Answered by puissant last updated on 07/Jul/21 $$\mid\mathrm{a}+\mathrm{b}\mid\leqslant\mid\mathrm{a}\mid+\mid\mathrm{b}\mid\:\Rightarrow\:\frac{\mid\mathrm{a}\mid+\mid\mathrm{b}\mid}{\mid\mathrm{a}+\mathrm{b}\mid}\:\geqslant\mathrm{1} \\ $$$$\Rightarrow\:\left(\frac{\mathrm{1}}{\mathrm{2}}+\frac{\mid\mathrm{a}\mid+\mid\mathrm{b}\mid}{\mid\mathrm{a}+\mathrm{b}\mid}\right)\geqslant\frac{\mathrm{3}}{\mathrm{2}} \\ $$$$\mathrm{take}\:\mathrm{min}=\frac{\mathrm{3}}{\mathrm{2}}..…

montrer-que-l-ensemble-des-suites-reelle-qui-verifie-la-relation-n-N-aU-n-2-bU-n-1-cU-n-0-1-est-un-espace-vectoriel-de-dimension-2-et-determiner-une-base-

Question Number 145522 by ArielVyny last updated on 05/Jul/21 $${montrer}\:{que}\:{l}'{ensemble}\:{des}\:{suites}\:{reelle}\:{qui} \\ $$$${verifie}\:{la}\:{relation}\:\forall{n}\in\mathbb{N} \\ $$$${aU}_{{n}+\mathrm{2}} +{bU}_{{n}+\mathrm{1}} +{cU}_{{n}} =\mathrm{0}\:\left(\mathrm{1}\right)\:\:{est}\:{un}\:{espace} \\ $$$${vectoriel}\:{de}\:{dimension}\:\mathrm{2} \\ $$$${et}\:{determiner}\:{une}\:{base}\: \\ $$$$ \\ $$…

Question-79974

Question Number 79974 by TawaTawa last updated on 29/Jan/20 Answered by Rio Michael last updated on 30/Jan/20 $$\:\boldsymbol{\mathrm{solution}} \\ $$$$\:\:\left[\left({p}\:\vee\:{q}\right)\:\wedge\:\left(\sim{p}\:\vee{r}\right)\right]\:\Rightarrow\:\left({q}\:\vee{r}\right) \\ $$$$\mathrm{we}\:\mathrm{know}\:\mathrm{from}\:\mathrm{known}\:\mathrm{facts}\:\mathrm{that}\: \\ $$$$\:−\left({p}\:\vee{q}\right)\:\mathrm{is}\:\mathrm{a}\:\mathrm{contingency}\:\left(\mathrm{neither}\:\mathrm{a}\:\mathrm{tautology}\:\mathrm{nor}\:\mathrm{contradiction}\right) \\…