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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




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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