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Author: Tinku Tara

An-Interesting-App-I-ve-recently-downloaded-the-app-called-Math-Tricks-from-the-Google-Play-Store-If-you-d-like-to-improve-your-speed-and-skill-in-the-mental-calculations-arena-I-think-this-app-s

Question Number 7230 by Yozzia last updated on 17/Aug/16 $${An}\:{Interesting}\:{App}: \\ $$$${I}'{ve}\:{recently}\:{downloaded}\:{the}\:{app}\:{called} \\ $$$$'{Math}\:{Tricks}'\:{from}\:{the}\:{Google}\:{Play}\:{Store}. \\ $$$${If}\:{you}'{d}\:{like}\:{to}\:{improve}\:{your}\:{speed} \\ $$$${and}\:{skill}\:{in}\:{the}\:{mental}\:{calculations} \\ $$$${arena},\:{I}\:{think}\:{this}\:{app}\:{should}\:{be}\:{of} \\ $$$${interest}\:{to}\:{you}.\:{The}\:{app}\:{can}\:{throw}\:{you}\:{simple} \\ $$$${calculations}\:{that}\:{include}\:{the}\:{basic}\:{operations} \\…

Question-138299

Question Number 138299 by cherokeesay last updated on 12/Apr/21 Answered by bemath last updated on 12/Apr/21 $${BD}\:=\:{r}_{\mathrm{1}} +\mathrm{2}\:\Leftrightarrow\:{r}_{\mathrm{1}} \left(\sqrt{\mathrm{2}}−\mathrm{1}\right)=\mathrm{2} \\ $$$${r}_{\mathrm{1}} =\:\frac{\mathrm{2}}{\:\sqrt{\mathrm{2}}−\mathrm{1}}\:=\:\frac{\mathrm{2}\left(\sqrt{\mathrm{2}}+\mathrm{1}\right)}{\mathrm{2}−\mathrm{1}}=\mathrm{2}\sqrt{\mathrm{2}}+\mathrm{2} \\ $$$${shaded}\:{area}=\left(\mathrm{2}\sqrt{\mathrm{2}}+\mathrm{2}\right)^{\mathrm{2}} −\frac{\mathrm{1}}{\mathrm{4}}\pi\left(\mathrm{2}\sqrt{\mathrm{2}}+\mathrm{2}\right)^{\mathrm{2}}…

Question-7216

Question Number 7216 by peter james last updated on 16/Aug/16 Answered by Yozzia last updated on 16/Aug/16 $${ln}\left({x}+{y}\right)−{ln}\left({x}+\mathrm{3}\right)+{ln}\mid\frac{\mathrm{3}−{y}}{{x}+\mathrm{3}}\mid={B}−{ln}\mid{x}+\mathrm{3}\mid \\ $$$${Let}\:{u}=\frac{{x}+{y}}{{x}+\mathrm{3}}\Rightarrow{y}={u}\left({x}+\mathrm{3}\right)−{x} \\ $$$$\therefore\:{y}'={u}'\left({x}+\mathrm{3}\right)+{u}−\mathrm{1} \\ $$$$\Rightarrow{y}'+\mathrm{1}={u}+{u}'\left({x}+\mathrm{3}\right). \\…

Let-a-and-b-be-positive-integers-such-that-ab-1-divides-a-2-b-2-Show-that-a-2-b-2-ab-1-is-the-square-of-an-integer-IMO-1988-Qu-6-

Question Number 7213 by Yozzia last updated on 16/Aug/16 $${Let}\:{a}\:{and}\:{b}\:{be}\:{positive}\:{integers}\:{such} \\ $$$${that}\:{ab}+\mathrm{1}\:{divides}\:{a}^{\mathrm{2}} +{b}^{\mathrm{2}} .\:{Show}\:{that} \\ $$$$\frac{{a}^{\mathrm{2}} +{b}^{\mathrm{2}} }{{ab}+\mathrm{1}}\:{is}\:{the}\:{square}\:{of}\:{an}\:{integer}. \\ $$$$\left({IMO}\:\mathrm{1988}\:{Qu}.\mathrm{6}\right) \\ $$ Terms of Service…