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Category: Algebra

If-x-2a-2-5-x-2a-2-7-0-x-a-2-8a-10-a-2-9a-11-Find-a-

Question Number 226536 by hardmath last updated on 02/Dec/25 $$\mathrm{If}\:\:\:\left(\mathrm{x}+\left(\mathrm{2a}^{\mathrm{2}} +\mathrm{5}\right)\right)\left(\mathrm{x}−\left(\mathrm{2a}^{\mathrm{2}} +\mathrm{7}\right)\right)\:\leqslant\:\mathrm{0} \\ $$$$\:\:\:\:\:\:\:\mathrm{x}\in\left[−\left(\mathrm{a}^{\mathrm{2}} +\mathrm{8a}−\mathrm{10}\right)\:;\:\left(\mathrm{a}^{\mathrm{2}} +\mathrm{9a}−\mathrm{11}\right)\right] \\ $$$$\mathrm{Find}:\:\boldsymbol{\mathrm{a}}\:=\:? \\ $$ Answered by gregori last updated…

Find-n-1-1-n-2n-1-2-

Question Number 226509 by hardmath last updated on 01/Dec/25 $$\mathrm{Find}:\:\:\:\underset{\boldsymbol{\mathrm{n}}=\mathrm{1}} {\overset{\infty} {\sum}}\:\frac{\mathrm{1}}{\mathrm{n}\centerdot\left(\mathrm{2n}\:+\:\mathrm{1}\right)^{\mathrm{2}} }\:=\:? \\ $$ Answered by mr W last updated on 01/Dec/25 $$\frac{\mathrm{1}}{{n}\left(\mathrm{2}{n}+\mathrm{1}\right)^{\mathrm{2}} }=\frac{{A}}{{n}}+\frac{{B}}{\mathrm{2}{n}+\mathrm{1}}+\frac{{C}}{\left(\mathrm{2}{n}+\mathrm{1}\right)^{\mathrm{2}}…

Question-226515

Question Number 226515 by mr W last updated on 01/Dec/25 Commented by Ghisom_ last updated on 02/Dec/25 $${S}_{{k}} =\underset{{n}=\mathrm{1}} {\overset{{k}} {\sum}}\:\frac{{n}}{{n}^{\mathrm{4}} +{n}^{\mathrm{2}} +\mathrm{1}}\:=\frac{{k}\left({k}+\mathrm{1}\right)}{\mathrm{2}\left({k}^{\mathrm{2}} +{k}+\mathrm{1}\right)} \\…

Question-226362

Question Number 226362 by Rojarani last updated on 26/Nov/25 Answered by Frix last updated on 26/Nov/25 $$\alpha=\sqrt{\mathrm{3}}\mathrm{e}^{−\mathrm{i}\frac{\mathrm{3}\pi}{\mathrm{4}}} \\ $$$$\beta=\sqrt{\mathrm{3}}\mathrm{e}^{\mathrm{i}\frac{\mathrm{3}\pi}{\mathrm{4}}} \\ $$$$\alpha^{{n}} +\beta^{{n}} =\mathrm{2}×\mathrm{3}^{\frac{{n}}{\mathrm{2}}} \mathrm{cos}\:\frac{\mathrm{3}{n}\pi}{\mathrm{4}} \\…