Question Number 21760 by Tinkutara last updated on 03/Oct/17 $$\mathrm{There}\:\mathrm{are}\:{m}\:\mathrm{points}\:\mathrm{on}\:\mathrm{the}\:\mathrm{line}\:{AB}\:\mathrm{and} \\ $$$${n}\:\mathrm{points}\:\mathrm{on}\:\mathrm{the}\:\mathrm{line}\:{AC},\:\mathrm{excluding}\:\mathrm{the} \\ $$$$\mathrm{point}\:{A}.\:\mathrm{Triangles}\:\mathrm{are}\:\mathrm{formed}\:\mathrm{joining} \\ $$$$\mathrm{these}\:\mathrm{points} \\ $$$$\left(\mathrm{i}\right)\:\mathrm{When}\:\mathrm{point}\:{A}\:\mathrm{is}\:\mathrm{not}\:\mathrm{included}, \\ $$$$\left(\mathrm{ii}\right)\:\mathrm{When}\:\mathrm{point}\:{A}\:\mathrm{is}\:\mathrm{included}. \\ $$$$\mathrm{The}\:\mathrm{ratio}\:\mathrm{of}\:\mathrm{the}\:\mathrm{number}\:\mathrm{of}\:\mathrm{such}\:\mathrm{triangles} \\ $$$$\mathrm{is} \\…
Question Number 152829 by liberty last updated on 01/Sep/21 Answered by MJS_new last updated on 02/Sep/21 $${z}^{\mathrm{2}} =\mathrm{1}−{x}^{\mathrm{2}} −{y}^{\mathrm{2}} \\ $$$$\Rightarrow\:{f}\left({x},\:{y},\:{z}\right)={x}^{\mathrm{2}} +{y}^{\mathrm{2}} +{x}+\mathrm{2}{y}−\mathrm{1} \\ $$$$\left(\mathrm{1}\right)\:\mathrm{obviously}\:{x}\geqslant\mathrm{0}\wedge{y}\geqslant\mathrm{0}\:\mathrm{to}\:\mathrm{get}\:\mathrm{a}\:\mathrm{maximum}…
Question Number 21759 by Tinkutara last updated on 03/Oct/17 $$\mathrm{A}\:\mathrm{block}\:\mathrm{of}\:\mathrm{mass}\:\mathrm{1}\:\mathrm{kg}\:\mathrm{is}\:\mathrm{pushed}\:\mathrm{against} \\ $$$$\mathrm{a}\:\mathrm{rough}\:\mathrm{vertical}\:\mathrm{wall}\:\mathrm{with}\:\mathrm{a}\:\mathrm{force}\:\mathrm{of}\:\mathrm{20} \\ $$$$\mathrm{N},\:\mathrm{coefficient}\:\mathrm{of}\:\mathrm{static}\:\mathrm{friction}\:\mathrm{being}\:\frac{\mathrm{1}}{\mathrm{4}}. \\ $$$$\mathrm{Another}\:\mathrm{horizontal}\:\mathrm{force}\:\mathrm{of}\:\mathrm{10}\:\mathrm{N}\:\mathrm{is} \\ $$$$\mathrm{applied}\:\mathrm{on}\:\mathrm{the}\:\mathrm{block}\:\mathrm{in}\:\mathrm{a}\:\mathrm{direction} \\ $$$$\mathrm{parallel}\:\mathrm{to}\:\mathrm{the}\:\mathrm{wall}.\:\mathrm{Will}\:\mathrm{the}\:\mathrm{block}\:\mathrm{move}? \\ $$$$\mathrm{If}\:\mathrm{yes},\:\mathrm{with}\:\mathrm{what}\:\mathrm{acceleration}?\:\mathrm{If}\:\mathrm{no}, \\ $$$$\mathrm{find}\:\mathrm{the}\:\mathrm{frictional}\:\mathrm{force}\:\mathrm{exerted}\:\mathrm{by}\:\mathrm{wall} \\…
Question Number 152828 by mathdanisur last updated on 01/Sep/21 $$\underset{\:\mathrm{1}} {\overset{\:\infty} {\int}}\:\frac{\sqrt{\mathrm{x}}\:\mathrm{ln}\:\mathrm{x}}{\mathrm{x}^{\mathrm{2}} +\mathrm{x}+\mathrm{1}}\:\mathrm{dx}\:=\:? \\ $$ Answered by Ar Brandon last updated on 01/Sep/21 $${f}\left(\kappa\right)=\int_{\mathrm{1}} ^{\infty}…
Question Number 21756 by FilupS last updated on 03/Oct/17 $$\mathrm{Prove}\:\mathrm{that}\:\mathrm{the}\:\mathrm{product}\:\mathrm{for}\:\mathrm{all} \\ $$$${n}\mathrm{th}\:\mathrm{roots}\:\mathrm{of}\:\mathrm{unity}\:\mathrm{is}\:\mathrm{equal}\:\mathrm{to}\:\mathrm{zero}, \\ $$$$\mathrm{except}\:{n}=\mathrm{1}. \\ $$$$\: \\ $$$$\mathrm{Note}: \\ $$$${U}_{{n}} =\left\{{e}^{\mathrm{2}{k}\pi{i}/{n}} \:\mid\:{k}\in\left\{\mathrm{1},\:\mathrm{2},\:…,\:{n}\right\}\right\} \\ $$$${x}^{{n}} =\mathrm{1}…
Question Number 152827 by mathdanisur last updated on 01/Sep/21 Answered by MJS_new last updated on 02/Sep/21 $${p}=\frac{{xy}}{{x}+{y}}\:\Leftrightarrow\:{y}=\frac{{px}}{{x}−{p}}\:\Leftrightarrow\:{x}=\frac{{py}}{{y}−{p}} \\ $$$$\Rightarrow\:{x}>{p}\wedge{y}>{p}\:\wedge\:\left({x}−{p}\right)\mid\left({px}\right)\:\wedge\:\left({y}−{p}\right)\mid\left({py}\right) \\ $$$$\Rightarrow \\ $$$$\left(\mathrm{1}\right)\:{y}={x}\:\Rightarrow\:{y}={x}=\mathrm{2}{p} \\ $$$$\left(\mathrm{2}\right)\:{y}={p}+\mathrm{1}\:\Rightarrow\:{x}={p}\left({p}+\mathrm{1}\right)…
Question Number 152826 by Tawa11 last updated on 01/Sep/21 An electric current passes through two voltmeters in series containing copper sulphate (CuSO₄) and silver nitrate…
Question Number 21750 by Tinkutara last updated on 02/Oct/17 $$\mathrm{Column}\:\mathrm{II}\:\mathrm{gives}\:\mathrm{five}\:\mathrm{arrangements}\:\mathrm{of} \\ $$$$\mathrm{two}\:\mathrm{blocks}\:{A}\:\mathrm{and}\:{B}.\:\mathrm{In}\:\mathrm{each} \\ $$$$\mathrm{arrangement}\:\mathrm{their}\:\mathrm{masses}\:\mathrm{are}\:\mathrm{3}\:\mathrm{kg}\:\mathrm{and} \\ $$$$\mathrm{2}\:\mathrm{kg}\:\mathrm{respectively}.\:\mathrm{Match}\:\mathrm{the}\:\mathrm{entries}\:\mathrm{in} \\ $$$$\mathrm{column}\:\mathrm{I}\:\mathrm{with}\:\mathrm{arrangements}\:\mathrm{in}\:\mathrm{column} \\ $$$$\mathrm{II}. \\ $$$$\boldsymbol{\mathrm{Column}}\:\boldsymbol{\mathrm{I}} \\ $$$$\left(\mathrm{A}\right)\:\mathrm{Force}\:\mathrm{on}\:{B}\:\mathrm{w}.\mathrm{r}.\mathrm{t}.\:{A}\:\mathrm{is}\:\mathrm{equal}\:\mathrm{to}\:\mathrm{force} \\…
Question Number 87285 by ajfour last updated on 03/Apr/20 Commented by ajfour last updated on 03/Apr/20 $${If}\:{regions}\:{A}\:{and}\:{B}\:{have}\:{equal} \\ $$$${areas},\:{determine}\:{R}/{r}\:. \\ $$ Answered by mr W…