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Category: Number Theory

Question-100179

Question Number 100179 by bobhans last updated on 25/Jun/20 Answered by john santu last updated on 25/Jun/20 $$\mathrm{Tools}\:\sqrt{\mathrm{A}+\sqrt{\mathrm{B}}}\:=\:\sqrt{\frac{\mathrm{1}}{\mathrm{2}}\left(\mathrm{A}+\sqrt{\mathrm{A}^{\mathrm{2}} −\mathrm{B}}\right)}\:+\sqrt{\frac{\mathrm{1}}{\mathrm{2}}\left(\mathrm{A}−\sqrt{\mathrm{A}^{\mathrm{2}} −\mathrm{B}}\right)} \\ $$$$\Rightarrow\sqrt{\mathrm{m}+\sqrt{\mathrm{m}^{\mathrm{2}} −\mathrm{1}}}\:=\:\sqrt{\frac{\mathrm{1}}{\mathrm{2}}\left(\mathrm{m}+\mathrm{1}\right)}+\sqrt{\frac{\mathrm{1}}{\mathrm{2}}\left(\mathrm{m}−\mathrm{1}\right)} \\ $$$$\underset{\mathrm{m}\:=\:\mathrm{1}\:}…

what-is-the-number-of-ordered-pairs-of-positif-integers-x-y-that-satisfy-x-2-y-2-xy-37-

Question Number 100178 by bobhans last updated on 25/Jun/20 $$\mathrm{what}\:\mathrm{is}\:\mathrm{the}\:\mathrm{number}\:\mathrm{of}\:\mathrm{ordered}\:\mathrm{pairs}\:\mathrm{of}\:\mathrm{positif}\: \\ $$$$\mathrm{integers}\:\left(\mathrm{x},\mathrm{y}\right)\:\mathrm{that}\:\mathrm{satisfy}\:\mathrm{x}^{\mathrm{2}} +\mathrm{y}^{\mathrm{2}} −\mathrm{xy}=\mathrm{37} \\ $$ Answered by 1549442205 last updated on 25/Jun/20 $$\mathrm{x}^{\mathrm{2}} −\mathrm{xy}+\mathrm{y}^{\mathrm{2}}…

Question-100042

Question Number 100042 by bobhans last updated on 24/Jun/20 Answered by Rasheed.Sindhi last updated on 25/Jun/20 $$\:\:\:\mathrm{16}{p}={r}^{\mathrm{3}} −\mathrm{1} \\ $$$$\:\:\:\:\mathrm{16}{p}=\left({r}−\mathrm{1}\right)\left({r}^{\mathrm{2}} +{r}+\mathrm{1}\right) \\ $$$$\:\:\:\:{r}−\mathrm{1}=\mathrm{1},\mathrm{2},\mathrm{4},\mathrm{8},\mathrm{16},{p} \\ $$$$\:{r}=\mathrm{2},\mathrm{3},\mathrm{5},\mathrm{9},\mathrm{17},{p}+\mathrm{1}\:\left(\mathrm{possible}\:\mathrm{values}\right)\:\:\:…

p-q-P-m-n-0-1-2-How-many-pairs-are-there-whose-LCM-is-p-m-q-n-when-i-a-b-amp-b-a-are-considered-same-ii-a-b-amp-b-a-are-considered-different-Generalization-of-Q-34358-

Question Number 34385 by Rasheed.Sindhi last updated on 05/May/18 $$\mathrm{p},\mathrm{q}\in\mathbb{P} \\ $$$$\mathrm{m},\mathrm{n}\in\left\{\mathrm{0},\mathrm{1},\mathrm{2},…\right\} \\ $$$$\mathrm{How}\:\mathrm{many}\:\mathrm{pairs}\:\mathrm{are}\:\mathrm{there},\mathrm{whose} \\ $$$$\mathrm{LCM}\:\mathrm{is}\:\mathrm{p}^{\mathrm{m}} \mathrm{q}^{\mathrm{n}\:} ,\mathrm{when}: \\ $$$$\left(\mathrm{i}\right)\left(\mathrm{a},\mathrm{b}\right)\:\&\:\left(\mathrm{b},\mathrm{a}\right)\:\mathrm{are}\:\mathrm{considered}\:\mathrm{same}. \\ $$$$\left(\mathrm{ii}\right)\left(\mathrm{a},\mathrm{b}\right)\:\&\:\left(\mathrm{b},\mathrm{a}\right)\:\mathrm{are}\:\mathrm{considered}\:\mathrm{different}. \\ $$$$\:\:\:\:\left(\mathrm{Generalization}\:\mathrm{of}\:\mathrm{Q}#\:\mathrm{34358}\right) \\…

Determine-number-of-possible-pairs-whose-GCD-is-144-in-case-i-when-a-b-and-b-a-is-considerd-same-ii-when-a-b-and-b-a-is-considerd-different-

Question Number 34369 by Rasheed.Sindhi last updated on 05/May/18 $$\mathrm{Determine}\:\mathrm{number}\:\mathrm{of}\:\mathrm{possible}\:\mathrm{pairs},\mathrm{whose} \\ $$$$\mathrm{GCD}\:\mathrm{is}\:\mathrm{144}\:\mathrm{in}\:\mathrm{case}: \\ $$$$\left(\mathrm{i}\right)\:\mathrm{when}\:\left(\mathrm{a},\mathrm{b}\right)\:\mathrm{and}\:\left(\mathrm{b},\mathrm{a}\right)\:\mathrm{is}\:\mathrm{considerd} \\ $$$$\:\:\:\:\:\:\:\mathrm{same}. \\ $$$$\left(\mathrm{ii}\right)\:\mathrm{when}\:\left(\mathrm{a},\mathrm{b}\right)\:\mathrm{and}\:\left(\mathrm{b},\mathrm{a}\right)\:\mathrm{is}\:\mathrm{considerd} \\ $$$$\:\:\:\:\:\:\:\:\:\mathrm{different}. \\ $$ Answered by MJS…

Determine-number-of-possible-pairs-whose-LCM-is-144-in-case-i-when-a-b-amp-b-a-are-considered-same-ii-when-a-b-amp-b-a-are-considered-different-

Question Number 34358 by Rasheed.Sindhi last updated on 05/May/18 $$\mathrm{Determine}\:\mathrm{number}\:\mathrm{of}\:\mathrm{possible}\:\mathrm{pairs}\:\mathrm{whose} \\ $$$$\mathrm{LCM}\:\mathrm{is}\:\mathrm{144}\:\mathrm{in}\:\mathrm{case}, \\ $$$$\left(\mathrm{i}\right)\mathrm{when}\:\left(\mathrm{a},\mathrm{b}\right)\:\&\:\left(\mathrm{b},\mathrm{a}\right)\:\mathrm{are}\:\mathrm{considered}\:\mathrm{same}. \\ $$$$\left(\mathrm{ii}\right)\mathrm{when}\left(\mathrm{a},\mathrm{b}\right)\:\&\:\left(\mathrm{b},\mathrm{a}\right)\:\mathrm{are}\:\mathrm{considered}\:\mathrm{different}. \\ $$ Commented by candre last updated on 05/May/18…

Let-x-1-0-x-2-1-and-x-n-1-2-x-n-1-x-n-2-Show-that-x-n-2-n-1-1-n-3-2-n-2-

Question Number 34186 by Joel578 last updated on 02/May/18 $$\mathrm{Let}\:{x}_{\mathrm{1}} \:=\:\mathrm{0},\:{x}_{\mathrm{2}} \:=\:\mathrm{1}\:\mathrm{and}\:{x}_{{n}} \:=\:\frac{\mathrm{1}}{\mathrm{2}}\left({x}_{{n}−\mathrm{1}} \:+\:{x}_{{n}−\mathrm{2}} \right) \\ $$$$\mathrm{Show}\:\mathrm{that}\: \\ $$$${x}_{{n}} \:=\:\frac{\mathrm{2}^{{n}−\mathrm{1}} \:+\:\left(−\mathrm{1}\right)^{{n}} }{\mathrm{3}\:.\:\mathrm{2}^{{n}−\mathrm{2}} } \\ $$…