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dx-x-2-4x-13-




Question Number 211546 by MrGaster last updated on 12/Sep/24
                                                  ∫(dx/( (√(x^2 −4x+13))))=?
dxx24x+13=?
Answered by Frix last updated on 12/Sep/24
∫(dx/( (√(x^2 −4x+13)))) =^([t=((x−2+(√(x^2 +4x+13)))/3)])    =∫(dt/t)=ln t =ln (x−2+(√(x^2 −4x+13))) +C
dxx24x+13=[t=x2+x2+4x+133]=dtt=lnt=ln(x2+x24x+13)+C
Answered by klipto last updated on 14/Sep/24
  using euler 1^(st)  sub  let  (√(x^2 −4x+13))=x+t  x^2 −4x+13=x^2 +2xt+t^2   (−4−2t)x=t^2 −13  x=((t^2 −13)/(−4−2t)), x+t=((t^2 −13)/(−4−2t))+(t/1)=((t^2 −13−4t−2t^2 )/(−4−2t))  =((−(t^2 +4t+13))/(−4−2t))  dx=(((−4−2t)(2t)−(t^2 −13)(−2))/((−4−2t)^2 ))dt  dx=((−8t−4t^2 +2t^2 −26)/((−4−2t)^2 ))dt=((−2t^2 −8t−26)/((−4−2t)^2 ))dt  =((−2(t^2 +4t+13))/((−4−2t)^2 ))dt  ∫((((−2(t^2 +4t+13))/((−4−2t)^2 ))dt)/((−(t^2 +4t+13))/(−4−2t)))=∫((−2(t^2 +4t+13)dt)/((−4−2t)^2 ))×((−4−2t)/(−(t^2 +4t+13)))  =∫(2/(−4−2t))×dt  u=−4−2t   (du/dt)=−2    dt=(du/(−2))  ∫(2/u)×(du/(−2))=−lnu=−ln(−4−2t)=ln(−)(4+2t)  =−ln(−4−2((√(x^2 −4x+13))+x)
usingeuler1stsubletx24x+13=x+tx24x+13=x2+2xt+t2(42t)x=t213x=t21342t,x+t=t21342t+t1=t2134t2t242t=(t2+4t+13)42tdx=(42t)(2t)(t213)(2)(42t)2dtdx=8t4t2+2t226(42t)2dt=2t28t26(42t)2dt=2(t2+4t+13)(42t)2dt2(t2+4t+13)(42t)2dt(t2+4t+13)42t=2(t2+4t+13)dt(42t)2×42t(t2+4t+13)=242t×dtu=42tdudt=2dt=du22u×du2=lnu=ln(42t)=ln()(4+2t)=ln(42(x24x+13+x)
Commented by Frix last updated on 14/Sep/24
Error in line 3 of the calculation:  (−4−2t)x=t^2 −13  [...and why not factorize? ⇒ x=((13−t^2 )/(2(t+2)))]
Errorinline3ofthecalculation:(42t)x=t213[andwhynotfactorize?x=13t22(t+2)]
Commented by klipto last updated on 14/Sep/24
seen my man,thanks,i do love to break  things down also so that others can comprehend
seenmyman,thanks,idolovetobreakthingsdownalsosothatotherscancomprehend
Commented by Frix last updated on 14/Sep/24
Near the end:  −ln (−4−2t) ≠ ln (4+2t)
Neartheend:ln(42t)ln(4+2t)
Commented by klipto last updated on 14/Sep/24
thanks my man,frix told you then that  let link up through whatsapp
thanksmyman,frixtoldyouthenthatletlinkupthroughwhatsapp
Commented by Frix last updated on 14/Sep/24
It would be easier to use  (√(x^2 −4x+13))=t−x ⇔ t=x+(√(x^2 −4x+13))  ⇒  x=((t^2 −13)/(2(t−2)))  dx=((√(x^2 −4x+13))/(x−2+(√(x^2 −4x+13))))dt=((√(x^2 −4x+13))/(t−2))dt  ⇒  ∫(dx/( (√(x^2 −4x+13))))=∫(dt/(t−2))=ln (t−2) =  =ln (x−2+(√(x^2 −4x+13))) +C
Itwouldbeeasiertousex24x+13=txt=x+x24x+13x=t2132(t2)dx=x24x+13x2+x24x+13dt=x24x+13t2dtdxx24x+13=dtt2=ln(t2)==ln(x2+x24x+13)+C
Commented by klipto last updated on 14/Sep/24
cool also
coolalso

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