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Category: Arithmetic

The-smallest-integer-numbers-with-n-2018-so-3-3i-n-form-real-numbers-is-

Question Number 55674 by gunawan last updated on 01/Mar/19 $$\mathrm{The}\:\mathrm{smallest}\:\mathrm{integer}\:\mathrm{numbers} \\ $$$$\mathrm{with}\:{n}\:\geqslant\:\mathrm{2018}\:\mathrm{so} \\ $$$$\left(\sqrt{\mathrm{3}}+\mathrm{3}{i}\right)^{{n}} \:\mathrm{form}\:\mathrm{real}\:\mathrm{numbers}\:\mathrm{is}.. \\ $$ Answered by mr W last updated on 02/Mar/19…

In-an-A-P-the-sum-of-the-first-50-terms-is-6275-Write-this-A-P-knowing-that-the-ratio-is-5-

Question Number 55628 by Mikael_Marshall last updated on 28/Feb/19 $${In}\:{an}\:{A}.{P},\:{the}\:{sum}\:{of}\:{the}\:{first}\:\mathrm{50}\:{terms}\:{is}\:\mathrm{6275}.\:{Write}\:\:{this}\:{A}.{P}\:.\:{knowing}\:{that}\:{the}\:{ratio}\:{is}\:\mathrm{5}. \\ $$ Answered by kaivan.ahmadi last updated on 28/Feb/19 $${s}_{{n}} =\frac{{n}}{\mathrm{2}}\left[\mathrm{2}{a}+\left({n}−\mathrm{1}\right){d}\right] \\ $$$$\mathrm{6275}=\mathrm{25}\left[\mathrm{2}{a}+\mathrm{49}×\mathrm{5}\right]=\mathrm{25}\left[\mathrm{2}{a}+\mathrm{245}\right]= \\ $$$$\mathrm{50}{a}+\mathrm{6145}\Rightarrow\mathrm{50}{a}=\mathrm{6275}−\mathrm{6145}=\mathrm{150}\Rightarrow…

show-by-recurrence-that-n-1-a-n-b-n-a-b-a-n-1-a-n-2-b-ab-n-2-b-n-1-

Question Number 121014 by mathocean1 last updated on 04/Nov/20 $$\mathrm{show}\:\mathrm{by}\:\mathrm{recurrence}\:\mathrm{that} \\ $$$$\forall\:\mathrm{n}\geqslant\mathrm{1}\:, \\ $$$$\mathrm{a}^{\mathrm{n}} −\mathrm{b}^{\mathrm{n}} =\left(\mathrm{a}−\mathrm{b}\right)\left(\mathrm{a}^{\mathrm{n}−\mathrm{1}} +\mathrm{a}^{\mathrm{n}−\mathrm{2}} \ast\mathrm{b}+…+\mathrm{ab}^{\mathrm{n}−\mathrm{2}} +\mathrm{b}^{\mathrm{n}−\mathrm{1}} \right) \\ $$ Answered by mathmax…

x-y-z-N-with-x-gt-3-are-numbers-we-suppose-that-y-is-equal-to-121-in-base-x-and-z-is-equal-to-110-in-base-x-1-show-that-we-can-write-without-knowing-x-the-product-xyz-in-base-x-2-we-su

Question Number 121012 by mathocean1 last updated on 04/Nov/20 $$\mathrm{x};\mathrm{y};\mathrm{z}\:\in\:\mathbb{N}^{\ast\:} \mathrm{with}\:\mathrm{x}>\mathrm{3}\:\mathrm{are}\: \\ $$$$\mathrm{numbers}. \\ $$$$\mathrm{we}\:\mathrm{suppose}\:\mathrm{that}\:\mathrm{y}\:\mathrm{is}\:\mathrm{equal} \\ $$$$\mathrm{to}\:\mathrm{121}\:\mathrm{in}\:\mathrm{base}\:\mathrm{x}\:\mathrm{and}\:\mathrm{z}\:\mathrm{is}\:\mathrm{equal} \\ $$$$\mathrm{to}\:\mathrm{110}\:\mathrm{in}\:\mathrm{base}\:\mathrm{x}. \\ $$$$\left.\mathrm{1}\right)\:\mathrm{show}\:\mathrm{that}\:\mathrm{we}\:\mathrm{can}\:\mathrm{write} \\ $$$$\left(\mathrm{without}\:\mathrm{knowing}\:\mathrm{x}\right)\:\mathrm{the}\: \\ $$$$\mathrm{product}\:\mathrm{xyz}\:\mathrm{in}\:\mathrm{base}\:\mathrm{x}.…

If-x-y-z-then-prove-the-following-inequality-x-2-2-y-2-2-z-2-2-9-xy-yz-xz-

Question Number 120847 by Jamshidbek2311 last updated on 03/Nov/20 $${If}\:{x},{y},{z}\:\:{then}\:{prove}\:{the}\:{following} \\ $$$${inequality} \\ $$$$\left({x}^{\mathrm{2}} +\mathrm{2}\right)\left({y}^{\mathrm{2}} +\mathrm{2}\right)\left({z}^{\mathrm{2}} +\mathrm{2}\right)=\mathrm{9}\left({xy}+{yz}+{xz}\right) \\ $$ Commented by Jamshidbek2311 last updated on…

QUIZ-If-the-sum-of-the-numbers-1-to-100-can-be-calculated-with-Carl-Gauss-s-method-then-How-do-we-calculate-the-sum-of-the-numbers-starting-from-2-and-going-up-to-100-by-twos-in-an-easy-way-with-the

Question Number 186348 by test1234 last updated on 03/Feb/23 $$\mathrm{Q}{UIZ}: \\ $$$${If}\:{the}\:{sum}\:{of}\:{the}\:{numbers}\:\mathrm{1}\:{to}\:\mathrm{100}\:{can} \\ $$$${be}\:{calculated}\:{with}\:{Carl}\:{Gauss}'{s}\:{method}, \\ $$$${then}\:{How}\:{do}\:{we}\:{calculate}\:{the}\:{sum}\:{of}\:{the} \\ $$$${numbers}\:{starting}\:{from}\:\mathrm{2}\:{and}\:{going}\:{up}\:{to} \\ $$$$\mathrm{100}\:{by}\:{twos}\:{in}\:{an}\:{easy}\:{way}\:{with}\:{the}\:{same} \\ $$$${method}? \\ $$$${Or}\:\mathrm{2}+\mathrm{4}+\mathrm{6}+\mathrm{8}+\mathrm{10}+…+\mathrm{100}=? \\…