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Question-propose-par-Migma-calcul-de-X-ABC-ACB-40-AB-2-AC-2-BC-2-2AC-BCcos-40-AC-15-AB-X-4-BC-10-X-4-2-15-2-10-2-300-cos-40-325-229-8

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Question Number 186486 by a.lgnaoui last updated on 05/Feb/23
Question propose par Migma −−−−−−−−−−− calcul de X △ABC ∡ACB=40^° AB^2 =AC^2 +BC^2 −2AC×BCcos 40 AC=15 ; AB=X+4 ; BC=10 (X+4)^2 =15^2 +10^2 −300×cos 40 =325−229,81334 (X+4)^2 =95,18666706 posons Z=X+4 Z^2 =9,756^2 ⇒X+4=9,756 X=5,756
$${Question}\:{propose}\:{par} \\ $$$${Migma} \\ $$$$−−−−−−−−−−− \\ $$$${calcul}\:{de}\:{X} \\ $$$$ \\ $$$$\bigtriangleup{ABC}\:\:\:\:\:\:\measuredangle{ACB}=\mathrm{40}^{°} \\ $$$$\mathrm{AB}^{\mathrm{2}} =\mathrm{AC}^{\mathrm{2}} +\mathrm{BC}^{\mathrm{2}} −\mathrm{2AC}×\mathrm{BCcos}\:\mathrm{40}\:\:\:\: \\ $$$$\mathrm{AC}=\mathrm{15}\:\:;\:\:\:\:\mathrm{AB}=\mathrm{X}+\mathrm{4}\:;\:\:\:\mathrm{BC}=\mathrm{10} \\ $$$$\left(\mathrm{X}+\mathrm{4}\right)^{\mathrm{2}} =\mathrm{15}^{\mathrm{2}} +\mathrm{10}^{\mathrm{2}} −\mathrm{300}×\mathrm{cos}\:\mathrm{40} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:=\mathrm{325}−\mathrm{229},\mathrm{81334} \\ $$$$\left({X}+\mathrm{4}\right)^{\mathrm{2}} =\mathrm{95},\mathrm{18666706} \\ $$$${posons}\:\:\:{Z}={X}+\mathrm{4} \\ $$$$\:\:\:{Z}^{\mathrm{2}} =\mathrm{9},\mathrm{756}^{\mathrm{2}} \:\:\:\:\Rightarrow\mathrm{X}+\mathrm{4}=\mathrm{9},\mathrm{756} \\ $$$$ \\ $$$$\:\:\:\:\:\:\:\:\:\:{X}=\mathrm{5},\mathrm{756} \\ $$$$ \\ $$
Commented by a.lgnaoui last updated on 05/Feb/23
Commented by mr W last updated on 05/Feb/23
it′s wrong and non−sense again. it′s adventurous how you treat mathematics! sometimes you just measure a figure and find that a triangle looks like equilateral and then you set it as equilateral and solve the question. in current case an angle is just marked as 4α, and you simply set it as 40° and solve the question, without taking other information and conditions into consideration. i′m sorry to say that you treat mathematics basically not as an exact and strict thing and thus in many cases your so−called solutions are just non−sense, which i don′t think you need to share, because such solutions will help nobody else in any way. i don′t want to disencourage you, i just think you should generally consider to take mathematics as a serious, exact and strict matter.
$${it}'{s}\:{wrong}\:{and}\:{non}−{sense}\:{again}. \\ $$$${it}'{s}\:{adventurous}\:{how}\:{you}\:{treat} \\ $$$${mathematics}!\:{sometimes}\:{you}\:{just} \\ $$$${measure}\:{a}\:{figure}\:{and}\:{find}\:{that}\:{a}\:{triangle} \\ $$$${looks}\:{like}\:{equilateral}\:{and}\:{then}\:{you} \\ $$$${set}\:{it}\:{as}\:{equilateral}\:{and}\:{solve}\:{the} \\ $$$${question}.\:{in}\:{current}\:{case}\:{an}\:{angle}\:{is}\: \\ $$$${just}\:{marked}\:{as}\:\mathrm{4}\alpha,\:{and}\:{you}\:{simply}\:{set}\: \\ $$$${it}\:{as}\:\mathrm{40}°\:{and}\:{solve}\:{the}\:{question},\: \\ $$$${without}\:{taking}\:{other}\:{information}\: \\ $$$${and}\:{conditions}\:{into}\:{consideration}.\: \\ $$$${i}'{m}\:{sorry}\:{to}\:{say}\:{that}\:{you}\:{treat}\: \\ $$$${mathematics}\:{basically}\:{not}\:{as}\:{an}\: \\ $$$${exact}\:{and}\:{strict}\:{thing}\:{and}\:{thus}\:{in}\: \\ $$$${many}\:{cases}\:{your}\:\:{so}−{called}\:{solutions}\: \\ $$$${are}\:{just}\:{non}−{sense},\:{which}\:{i}\:{don}'{t} \\ $$$${think}\:{you}\:{need}\:{to}\:{share},\:{because} \\ $$$${such}\:{solutions}\:{will}\:{help}\:{nobody}\:{else}\: \\ $$$${in}\:{any}\:{way}. \\ $$$${i}\:{don}'{t}\:{want}\:{to}\:{disencourage}\:{you},\: \\ $$$${i}\:{just}\:{think}\:{you}\:{should}\:{generally} \\ $$$${consider}\:{to}\:{take}\:{mathematics}\:{as}\:{a} \\ $$$${serious},\:{exact}\:{and}\:{strict}\:{matter}. \\ $$
Commented by a.lgnaoui last updated on 05/Feb/23
there is many way to have a solutiin but and my methode is correct perhapse you prefere your methode but do not say that mine is wrong I have trying authere similar methode and I had founding the same resultat but the radical complexe the resultat so I had prefer this all can resolve with his methode (raisonnable ) with tools and lows(lois)mathematics and Excuse me and all autere for the probleme of language english because I had studing with langage Arabic and frensh but this was not a principal probleme I comment some questions posting by frends and I add (like)when I receive the answer If any answers are not exact(correct) the <intervenants> can samply give her ideas to explain why the answer is thrue or not I practisse mathematic because I like it and not simply to look the answers. −Ahmed LAGNAOUI− Membre in forum: Editeur Mathematique. −−−−−−−−−End.
$${there}\:{is}\:{many}\:{way}\:{to}\:{have}\:{a}\:{solutiin} \\ $$$${but}\:{and}\:{my}\:{methode}\:{is} \\ $$$${correct}\:{perhapse}\:{you}\:{prefere} \\ $$$${your}\:{methode}\:{but}\:{do}\:{not} \\ $$$${say}\:{that}\:{mine}\:{is}\:{wrong} \\ $$$${I}\:{have}\:{trying}\:{authere}\:{similar} \\ $$$${methode}\:\:{and}\:{I}\:{had}\:{founding}\:{the}\:{same}\:{resultat}\:{but}\:{the}\:{radical} \\ $$$${complexe}\:{the}\:{resultat} \\ $$$${so}\:{I}\:{had}\:{prefer}\:{this}\: \\ $$$${all}\:{can}\:{resolve}\:{with}\:{his} \\ $$$${methode}\:\left({raisonnable}\:\right) \\ $$$${with}\:{tools}\:{and}\:{lows}\left({lois}\right){mathematics} \\ $$$${and}\:{Excuse}\:{me}\:{and}\:{all}\: \\ $$$${autere}\:{for}\:{the}\:{probleme}\:{of} \\ $$$${language}\:{english}\:{because} \\ $$$${I}\:{had}\:{studing}\:{with}\:{langage} \\ $$$${Arabic}\:{and}\:{frensh}\:\:{but}\:{this} \\ $$$${was}\:{not}\:{a}\:{principal}\:{probleme} \\ $$$${I}\:{comment}\:{some}\:{questions} \\ $$$${posting}\:{by}\:\:{frends}\:\:{and}\: \\ $$$${I}\:{add}\:\left({like}\right){when}\:{I}\:{receive} \\ $$$${the}\:{answer}\: \\ $$$${If}\:{any}\:{answers}\:{are}\:{not}\: \\ $$$${exact}\left({correct}\right)\:{the}\:<{intervenants}> \\ $$$${can}\:{samply}\:\:{give}\:{her}\:{ideas}\:{to}\:{explain} \\ $$$${why}\:{the}\:{answer}\:{is}\:{thrue}\:{or}\:{not} \\ $$$${I}\:{practisse}\:{mathematic} \\ $$$${because}\:{I}\:{like}\:{it}\:{and}\:{not}\: \\ $$$${simply}\:{to}\:{look}\:{the}\:{answers}. \\ $$$$−{Ahmed}\:{LAGNAOUI}− \\ $$$${Membre}\:{in}\:{forum}: \\ $$$${Editeur}\:{Mathematique}. \\ $$$$−−−−−−−−−{End}. \\ $$
Commented by mr W last updated on 05/Feb/23
since the forum is a public place, it is normal and even expected that one′s posts (solutions or comments) are commented by others. i′m not talking about if a method is good or bad, in current case it is not a method at all, but just non−sense, that an angle, which is marked as 4α simply taken as an angle of 40°. since this is presented in forum as solution, i think it is allowed for me to say it is wrong. when this is inappropriate for you, i say i′m sorry and won′t comment any more in future.
$${since}\:{the}\:{forum}\:{is}\:{a}\:{public}\:{place}, \\ $$$${it}\:{is}\:{normal}\:{and}\:{even}\:{expected}\:{that} \\ $$$${one}'{s}\:{posts}\:\left({solutions}\:{or}\:{comments}\right) \\ $$$${are}\:{commented}\:{by}\:{others}.\:{i}'{m}\:{not} \\ $$$${talking}\:{about}\:{if}\:{a}\:{method}\:{is}\:{good} \\ $$$${or}\:{bad},\:{in}\:{current}\:{case}\:{it}\:{is}\:{not} \\ $$$${a}\:{method}\:{at}\:{all},\:{but}\:{just}\:{non}−{sense}, \\ $$$${that}\:{an}\:{angle},\:{which}\:{is}\:{marked}\:{as}\: \\ $$$$\mathrm{4}\alpha\:{simply}\:{taken}\:{as}\:{an}\:{angle}\:{of}\:\mathrm{40}°. \\ $$$${since}\:{this}\:{is}\:{presented}\:{in}\:{forum}\:{as} \\ $$$${solution},\:{i}\:{think}\:{it}\:{is}\:{allowed}\:{for}\:{me} \\ $$$${to}\:{say}\:{it}\:{is}\:{wrong}.\:{when}\:{this}\:{is}\: \\ $$$${inappropriate}\:{for}\:{you},\:{i}\:{say}\:{i}'{m}\:{sorry} \\ $$$${and}\:{won}'{t}\:{comment}\:{any}\:{more}\:{in}\: \\ $$$${future}. \\ $$
Commented by Frix last updated on 05/Feb/23
There are many ways to find a solution but most of the time there is only one solution. If your way doesn′t lead to this solution ⇒ your way is wrong. But there are also rules. If you don′t obey the rules of a certain game, you′re playing a different game instead. If the king on your chessboard moves like a knight you′re not playing chess. You don′t follow the rules of mathematics very often ⇒ you′re not doing mathematics.
$$\mathrm{There}\:\mathrm{are}\:\mathrm{many}\:\mathrm{ways}\:\mathrm{to}\:\mathrm{find}\:\mathrm{a}\:\mathrm{solution}\:\mathrm{but} \\ $$$$\mathrm{most}\:\mathrm{of}\:\mathrm{the}\:\mathrm{time}\:\mathrm{there}\:\mathrm{is}\:\mathrm{only}\:\mathrm{one}\:\mathrm{solution}. \\ $$$$\mathrm{If}\:\mathrm{your}\:\mathrm{way}\:\mathrm{doesn}'\mathrm{t}\:\mathrm{lead}\:\mathrm{to}\:\mathrm{this}\:\mathrm{solution} \\ $$$$\Rightarrow\:\mathrm{your}\:\mathrm{way}\:\mathrm{is}\:\mathrm{wrong}. \\ $$$$\mathrm{But}\:\mathrm{there}\:\mathrm{are}\:\mathrm{also}\:\mathrm{rules}.\:\mathrm{If}\:\mathrm{you}\:\mathrm{don}'\mathrm{t}\:\mathrm{obey} \\ $$$$\mathrm{the}\:\mathrm{rules}\:\mathrm{of}\:\mathrm{a}\:\mathrm{certain}\:\mathrm{game},\:\mathrm{you}'\mathrm{re}\:\mathrm{playing} \\ $$$$\mathrm{a}\:\mathrm{different}\:\mathrm{game}\:\mathrm{instead}.\:\mathrm{If}\:\mathrm{the}\:\mathrm{king}\:\mathrm{on} \\ $$$$\mathrm{your}\:\mathrm{chessboard}\:\mathrm{moves}\:\mathrm{like}\:\mathrm{a}\:\mathrm{knight}\:\mathrm{you}'\mathrm{re} \\ $$$$\mathrm{not}\:\mathrm{playing}\:\mathrm{chess}. \\ $$$$\mathrm{You}\:\mathrm{don}'\mathrm{t}\:\mathrm{follow}\:\mathrm{the}\:\mathrm{rules}\:\mathrm{of}\:\mathrm{mathematics} \\ $$$$\mathrm{very}\:\mathrm{often}\:\Rightarrow\:\mathrm{you}'\mathrm{re}\:\mathrm{not}\:\mathrm{doing}\:\mathrm{mathematics}. \\ $$
Commented by a.lgnaoui last updated on 05/Feb/23
with 4α authere solution Now I understand where is error
$${with}\:\mathrm{4}\alpha\:{authere}\:{solution} \\ $$$${Now}\:{I}\:{understand}\:{where}\:{is}\:{error} \\ $$$$ \\ $$

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