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Category: Algebra

Question-198030

Question Number 198030 by hardmath last updated on 08/Oct/23 Answered by Mathspace last updated on 09/Oct/23 $${let}\:\sqrt{{arcsinx}}={t}\:\Rightarrow{x}={sin}\left({t}^{\mathrm{2}} \right) \\ $$$${and}\:{I}=\int_{\sqrt{{arcsint}}} ^{\sqrt{{arcsin}\left({t}^{\mathrm{2}} \right)}} \:\:\:\frac{{t}}{{sin}\left({t}^{\mathrm{2}} \right)\left({sin}\left({t}^{\mathrm{2}} \right)−\mathrm{1}\right)}\mathrm{2}{tcos}\left({t}^{\mathrm{2}}…

Question-198031

Question Number 198031 by cortano12 last updated on 08/Oct/23 Answered by AST last updated on 08/Oct/23 $${a}^{\mathrm{2}} +{b}^{\mathrm{2}} =\mathrm{20}{ab}\Rightarrow\left({a}−{b}\right)^{\mathrm{2}} =\mathrm{18}{ab}…\left({i}\right) \\ $$$${a}^{\mathrm{3}} +{b}^{\mathrm{3}} =\mathrm{19}{ab}\Rightarrow\left({a}+{b}\right)\left({a}^{\mathrm{2}} +{b}^{\mathrm{2}}…

Question-198014

Question Number 198014 by hardmath last updated on 07/Oct/23 Answered by mahdipoor last updated on 07/Oct/23 $$=\underset{{x}=−\mathrm{1}} {\overset{−\infty} {\sum}}\left(\underset{{y}={x}−\mathrm{1}} {\overset{−\infty} {\sum}}\mathrm{2}^{{x}+\mathrm{1}} ×\mathrm{3}^{{y}} ×\mathrm{5}\right)=\mathrm{5}\left(\underset{{x}=−\mathrm{1}} {\overset{−\infty} {\sum}}\mathrm{2}^{{x}+\mathrm{1}}…

Question-197982

Question Number 197982 by hardmath last updated on 07/Oct/23 Answered by witcher3 last updated on 11/Oct/23 $$\mathrm{sin}\left(\frac{\mathrm{12}\pi}{\mathrm{180}}\right)\mathrm{sin}\left(\frac{\mathrm{15}\pi}{\mathrm{180}}\right)\mathrm{sin}\left(\frac{\mathrm{51}\pi}{\mathrm{180}}\right)\mathrm{sin}\left(\frac{\mathrm{57}\pi}{\mathrm{180}}\right)\mathrm{sin}\left(\frac{\mathrm{63}\pi}{\mathrm{180}}\right) \\ $$$$\mathrm{sin}\left(\frac{\mathrm{2}\pi}{\mathrm{60}}\right)\mathrm{sin}\left(\frac{\mathrm{5}\pi}{\mathrm{60}}\right)\mathrm{sin}\left(\frac{\mathrm{17}\pi}{\mathrm{60}}\right)\mathrm{sin}\left(\frac{\mathrm{19}\pi}{\mathrm{60}}\right)\mathrm{sin}\left(\frac{\mathrm{21}\pi}{\mathrm{60}}\right) \\ $$$$\mathrm{sin}\left(\frac{\mathrm{2}\pi}{\mathrm{60}}\right)=\mathrm{sin}\left(\frac{\pi}{\mathrm{30}}\right)=\mathrm{sin}\left(\frac{\pi}{\mathrm{5}}−\frac{\pi}{\mathrm{6}}\right) \\ $$$$\mathrm{sin}\left(\frac{\mathrm{5}\pi}{\mathrm{60}}\right)=\mathrm{sin}\left(\frac{\pi}{\mathrm{12}}\right)=\mathrm{sin}\left(\frac{\pi}{\mathrm{3}}−\frac{\pi}{\mathrm{4}}\right) \\ $$$$\mathrm{sin}\left(\frac{\mathrm{17}\pi}{\mathrm{60}}\right)=\mathrm{sin}\left(\frac{\pi}{\mathrm{5}}+\frac{\pi}{\mathrm{12}}\right)…

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Question Number 197960 by a.lgnaoui last updated on 06/Oct/23 $$\mathrm{determiner}\:\mathrm{le}\:\mathrm{total}\:\mathrm{de}\:\mathrm{nombres}\:\mathrm{de}\: \\ $$$$\mathrm{5}\:\mathrm{chiffres}\:\mathrm{comprises}\:\mathrm{entre}\:\mathrm{10000}\:\mathrm{et}\: \\ $$$$\mathrm{50000}\:\:\mathrm{divisibles}\:\mathrm{simultanement}\:\mathrm{par} \\ $$$$\mathrm{5}\:\mathrm{et}\:\mathrm{9}\:\:\: \\ $$$$\left(\mathrm{sans}\:\mathrm{utiliser}\:\mathrm{les}\:\mathrm{formules}\:\mathrm{d}\:\mathrm{arrangement}\right. \\ $$$$\left.\mathrm{et}\:\mathrm{de}\:\mathrm{combinaison}\right) \\ $$$$ \\ $$ Answered…

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Question Number 197935 by Frix last updated on 04/Oct/23 $$\mathrm{Show}\:\mathrm{that} \\ $$$$\underset{{n}=\mathrm{1}} {\overset{\infty} {\sum}}\:\frac{\left({n}!\right)^{\mathrm{2}} }{\left(\mathrm{2}{n}\right)!}\:=\frac{\mathrm{1}}{\mathrm{3}}+\frac{\mathrm{2}\pi\sqrt{\mathrm{3}}}{\mathrm{27}} \\ $$ Answered by witcher3 last updated on 05/Oct/23 $$\underset{\mathrm{n}\geqslant\mathrm{1}}…

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Question Number 197880 by universe last updated on 02/Oct/23 $$\mathrm{find}\:\mathrm{the}\:\mathrm{sum}\:\mathrm{of}\:\mathrm{infinite}\:\mathrm{series} \\ $$$$\:\frac{\mathrm{1}}{\mathrm{2}^{\mathrm{1}} }\centerdot\frac{\mathrm{1}}{\mathrm{3}^{\mathrm{2}} }\:+\:\frac{\mathrm{1}}{\mathrm{2}^{\mathrm{2}} }\centerdot\frac{\mathrm{1}}{\mathrm{3}^{\mathrm{4}} }\left(\mathrm{1}^{\mathrm{2}} +\mathrm{2}^{\mathrm{2}} +\mathrm{3}^{\mathrm{2}} \right)\:+\:\frac{\mathrm{1}}{\mathrm{2}^{\mathrm{3}} }\centerdot\frac{\mathrm{1}}{\mathrm{3}^{\mathrm{6}} }\left(\mathrm{1}^{\mathrm{2}} +\mathrm{2}^{\mathrm{2}} +\mathrm{3}^{\mathrm{2}} +…+\mathrm{7}^{\mathrm{2}} \right)+…