Question Number 66875 by Cmr 237 last updated on 20/Aug/19 Commented by mathmax by abdo last updated on 20/Aug/19 $${convergence}\:{of}\:{this}\:{serie}\:\:\:{let}\:\varphi\left({t}\right)\:=\frac{\mathrm{1}}{{t}^{\mathrm{3}} {sin}^{\mathrm{2}} {t}}\:\:{with}\:{t}>\mathrm{1} \\ $$$${we}\:{have}\:\varphi^{'} \left({t}\right)\:=\:−\frac{\mathrm{3}{t}^{\mathrm{2}}…
Question Number 132410 by bramlexs22 last updated on 14/Feb/21 $$\:\int_{\mathrm{0}} ^{\:\infty} \:\frac{\mathrm{dx}}{\left(\mathrm{x}^{\mathrm{4}} −\mathrm{x}^{\mathrm{2}} +\mathrm{1}\right)^{\mathrm{2}} }\: \\ $$ Answered by EDWIN88 last updated on 14/Feb/21 $$\mathrm{I}=\int_{\mathrm{0}}…
Question Number 1335 by 123456 last updated on 23/Jul/15 $$\mathrm{if}\:{a}\leqslant{x}\leqslant{b}\:\mathrm{and}\:{c}\leqslant{y}\leqslant{d}\:\mathrm{then}\:\mathrm{did} \\ $$$$\frac{{a}}{{d}}\leqslant\frac{{x}}{{y}}\leqslant\frac{{b}}{{c}}? \\ $$$${a},{b},{c},{d},{x},{y}\in\mathbb{R} \\ $$$$\mathrm{0}<{c} \\ $$$$\mathrm{0}<{a} \\ $$ Answered by prakash jain last…
Question Number 132407 by bramlexs22 last updated on 14/Feb/21 $$\mathrm{on}\:\mathrm{circle}\:\mathrm{x}^{\mathrm{2}} \:+\:\mathrm{y}^{\mathrm{2}} \:=\:\mathrm{25}\:,\:\mathrm{find}\:\mathrm{the}\:\mathrm{point} \\ $$$$\mathrm{closest}\:\mathrm{to}\:\left(\mathrm{1},\mathrm{1}\right). \\ $$ Answered by EDWIN88 last updated on 14/Feb/21 $$\mathrm{let}\:\mathrm{P}\left(\mathrm{x},\mathrm{y}\right)\:\mathrm{be}\:\mathrm{a}\:\mathrm{point}\:\mathrm{on}\:\mathrm{a}\:\mathrm{circle}\: \\…
Question Number 66868 by John Kaloki Musau last updated on 20/Aug/19 $${A}\:{town}\:{N}\:{is}\:\mathrm{340}{km}\:{due}\:{west}\:{of}\: \\ $$$${town}\:{G}\:{and}\:{town}\:{K}\:{is}\:{due}\:{west}\: \\ $$$${of}\:{town}\:{N}.\:{A}\:{helicopter}\:{Zebra}\: \\ $$$${left}\:{G}\:{for}\:{K}\:{at}\:\mathrm{9}{a}.{m}.\:{Another}\: \\ $$$${helicopter}\:{Buffalo}\:{left}\:{N}\:{for}\:{K} \\ $$$${at}\:\mathrm{11}{a}.{m}.\:{Helicopter}\:{Buffalo} \\ $$$${travelled}\:{at}\:{an}\:{average}\:{speed}\:{of}\: \\…
Question Number 66866 by rajesh4661kumar@gmail.com last updated on 20/Aug/19 Commented by mathmax by abdo last updated on 20/Aug/19 $${first}\:\:{x}+\sqrt{\mathrm{1}+{x}^{\mathrm{2}} }>\mathrm{0}\:\:{for}\:{all}\:{x}\:{so}\:{y}={ln}\left({x}+\sqrt{\mathrm{1}+{x}^{\mathrm{2}} }\right)={argsh}\left({x}\right)\:\Rightarrow \\ $$$${y}^{'} \left({x}\right)=\frac{\mathrm{1}}{\:\sqrt{\mathrm{1}+{x}^{\mathrm{2}} }}\:=\left(\mathrm{1}+{x}^{\mathrm{2}}…
Question Number 1331 by a@b.c last updated on 23/Jul/15 $$\mathrm{If}\:\alpha\:\mathrm{and}\:\beta\:\mathrm{are}\:\mathrm{different}\:\mathrm{complex}\:\mathrm{numbers} \\ $$$$\mathrm{with}\:\mid\beta\mid=\mathrm{1}\:\mathrm{then}\:\mid\frac{\beta−\alpha}{\mathrm{1}−\alpha\beta}\mid=? \\ $$ Commented by 123456 last updated on 23/Jul/15 $$\mid\alpha+\beta\mid\leqslant\mid\alpha\mid+\mid\beta\mid \\ $$$$\mid\beta−\alpha\mid\leqslant\mid\beta\mid+\mid\alpha\mid \\…
Question Number 132402 by bramlexs22 last updated on 14/Feb/21 $$\mathrm{Find}\:\mathrm{the}\:\mathrm{circumference}\:\mathrm{of}\:\mathrm{an} \\ $$$$\mathrm{ellipse}\:\frac{\left(\mathrm{x}−\mathrm{2}\right)^{\mathrm{2}} }{\mathrm{16}}+\frac{\mathrm{y}^{\mathrm{2}} }{\mathrm{25}}\:=\:\mathrm{1} \\ $$ Commented by mr W last updated on 14/Feb/21 $${the}\:{perimeter}\:{of}\:{an}\:{ellipse}\:{can}\:{not}…
Question Number 66865 by John Kaloki Musau last updated on 20/Aug/19 $${A}\:{and}\:{B}\:{are}\:{two}\:{towns}\:\mathrm{360}{km}\:{apart}. \\ $$$${An}\:{express}\:{bus}\:{departs}\:{from}\:{A}\:{at} \\ $$$$\mathrm{8}{a}.{m}\:{and}\:{maintains}\:{an}\:{average} \\ $$$${speed}\:{of}\:\mathrm{90}{km}/{h}\:{between}\:{A}\:{and}\:{B}. \\ $$$${Another}\:{bus}\:{starts}\:{from}\:{B}\:{also}\:{at} \\ $$$$\mathrm{8}{a}.{m}\:{and}\:{moves}\:{towards}\:{A}\:{making} \\ $$$${four}\:{stops}\:{at}\:{four}\:{equally}\:{spaced} \\…
Question Number 66862 by Aman Arya last updated on 20/Aug/19 $$\underset{{x}\rightarrow\mathrm{0}} {\mathrm{lim}3}{x}^{\mathrm{5}} \\ $$ Commented by mathmax by abdo last updated on 20/Aug/19 $$=\mathrm{3}×\mathrm{0}=\mathrm{0} \\…