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Category: Number Theory

Find-the-number-of-positive-integers-that-are-factors-of-3-19-7-12-10-25-and-are-also-multiples-of-3-15-7-10-10-19-

Question Number 199311 by necx122 last updated on 01/Nov/23 $${Find}\:{the}\:{number}\:{of}\:{positive}\:{integers} \\ $$$${that}\:{are}\:{factors}\:{of}\:\mathrm{3}^{\mathrm{19}} .\mathrm{7}^{\mathrm{12}} .\mathrm{10}^{\mathrm{25}} \:{and}\:{are} \\ $$$${also}\:{multiples}\:{of}\:\mathrm{3}^{\mathrm{15}} .\mathrm{7}^{\mathrm{10}} .\mathrm{10}^{\mathrm{19}} \\ $$ Answered by AST last…

Sum-of-two-irrational-numbers-is-1-less-than-their-product-and-8-less-than-their-sum-of-squares-Find-the-larger-of-the-two-numbers-

Question Number 199011 by necx122 last updated on 26/Oct/23 $${Sum}\:{of}\:{two}\:{irrational}\:{numbers}\:{is}\:\mathrm{1} \\ $$$${less}\:{than}\:{their}\:{product},\:{and}\:\mathrm{8}\:{less}\:{than} \\ $$$${their}\:{sum}\:{of}\:{squares}.\:{Find}\:{the}\:{larger} \\ $$$${of}\:{the}\:{two}\:{numbers}. \\ $$ Commented by nikif99 last updated on 27/Oct/23…

20-11-1-mod-1000-

Question Number 198400 by cortano12 last updated on 19/Oct/23 $$\:\:\mathrm{20}^{\mathrm{11}} −\mathrm{1}\:=\:…\left(\mathrm{mod}\:\mathrm{1000}\right) \\ $$ Answered by MM42 last updated on 19/Oct/23 $$\mathrm{20}^{\mathrm{11}} −\mathrm{1}\overset{\mathrm{1000}} {\equiv}−\mathrm{1}\overset{\mathrm{1000}} {\equiv}\mathrm{999} \\…

find-minimum-value-of-m-such-that-m-19-1800-mod-2029-

Question Number 197752 by cortano12 last updated on 27/Sep/23 $$\:\mathrm{find}\:\mathrm{minimum}\:\mathrm{value}\:\mathrm{of}\:\mathrm{m} \\ $$$$\:\mathrm{such}\:\mathrm{that}\:\mathrm{m}^{\mathrm{19}} =\:\mathrm{1800}\:\left(\mathrm{mod}\:\mathrm{2029}\right) \\ $$ Answered by AST last updated on 27/Sep/23 $${m}^{\mathrm{2028}} =\left({m}^{\mathrm{19}} \right)^{\mathrm{107}}…

Prove-that-x-0-lnt-t-2-1-dt-pi-2-0-arctan-xtan-d-x-1-x-lnt-t-2-1-arctant-dt-pi-8-pi-0-arctan-1-2-x-1-x-sint-dt-

Question Number 197461 by Erico last updated on 18/Sep/23 $$\mathrm{Prove}\:\mathrm{that}: \\ $$$$\bullet\underset{\:\mathrm{0}} {\int}^{\:\mathrm{x}} \frac{\mathrm{lnt}}{\mathrm{t}^{\mathrm{2}} −\mathrm{1}}\mathrm{dt}=\underset{\:\mathrm{0}} {\int}^{\:\frac{\pi}{\mathrm{2}}} \mathrm{arctan}\left(\mathrm{xtan}\theta\right)\mathrm{d}\theta \\ $$$$\bullet\:\:\underset{\:\frac{\mathrm{1}}{\mathrm{x}}} {\int}^{\:\mathrm{x}} \frac{\mathrm{lnt}}{\mathrm{t}^{\mathrm{2}} −\mathrm{1}}\mathrm{arctant}\:\mathrm{dt}=\frac{\pi}{\mathrm{8}}\underset{\:\mathrm{0}} {\int}^{\:\pi} \mathrm{arctan}\left(\frac{\mathrm{1}}{\mathrm{2}}\left(\mathrm{x}−\frac{\mathrm{1}}{\mathrm{x}}\right)\mathrm{sint}\right)\mathrm{dt} \\…