Help rearranging algebraic expression?!












1












$begingroup$


In the following relationship x and $delta_S$ are unknowns:



$$delta_f = delta_S-(delta_S-delta_o)expleft[-(1+mx)frac{It}{V}right]$$



I need to solve for x and have the following relationship for $delta_S$:



$$delta_S =frac{delta_{in}+mxdelta^*}{1+mx}$$



Therefore: $$delta_f = bigg(frac{(delta_{in}+mxdelta^*)}{(1+mx)}bigg)-bigg(frac{(delta_{in}+mxdelta^*)}{(1+mx)}-delta_ibigg)expbigg[-(1+mx)frac{It}{V}bigg]$$



Honestly I have no idea where to begin isolating x once I start taking the natural log...










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$endgroup$

















    1












    $begingroup$


    In the following relationship x and $delta_S$ are unknowns:



    $$delta_f = delta_S-(delta_S-delta_o)expleft[-(1+mx)frac{It}{V}right]$$



    I need to solve for x and have the following relationship for $delta_S$:



    $$delta_S =frac{delta_{in}+mxdelta^*}{1+mx}$$



    Therefore: $$delta_f = bigg(frac{(delta_{in}+mxdelta^*)}{(1+mx)}bigg)-bigg(frac{(delta_{in}+mxdelta^*)}{(1+mx)}-delta_ibigg)expbigg[-(1+mx)frac{It}{V}bigg]$$



    Honestly I have no idea where to begin isolating x once I start taking the natural log...










    share|cite|improve this question











    $endgroup$















      1












      1








      1





      $begingroup$


      In the following relationship x and $delta_S$ are unknowns:



      $$delta_f = delta_S-(delta_S-delta_o)expleft[-(1+mx)frac{It}{V}right]$$



      I need to solve for x and have the following relationship for $delta_S$:



      $$delta_S =frac{delta_{in}+mxdelta^*}{1+mx}$$



      Therefore: $$delta_f = bigg(frac{(delta_{in}+mxdelta^*)}{(1+mx)}bigg)-bigg(frac{(delta_{in}+mxdelta^*)}{(1+mx)}-delta_ibigg)expbigg[-(1+mx)frac{It}{V}bigg]$$



      Honestly I have no idea where to begin isolating x once I start taking the natural log...










      share|cite|improve this question











      $endgroup$




      In the following relationship x and $delta_S$ are unknowns:



      $$delta_f = delta_S-(delta_S-delta_o)expleft[-(1+mx)frac{It}{V}right]$$



      I need to solve for x and have the following relationship for $delta_S$:



      $$delta_S =frac{delta_{in}+mxdelta^*}{1+mx}$$



      Therefore: $$delta_f = bigg(frac{(delta_{in}+mxdelta^*)}{(1+mx)}bigg)-bigg(frac{(delta_{in}+mxdelta^*)}{(1+mx)}-delta_ibigg)expbigg[-(1+mx)frac{It}{V}bigg]$$



      Honestly I have no idea where to begin isolating x once I start taking the natural log...







      logarithms exponential-function factoring






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      edited Jan 19 at 1:58









      Larry

      2,41331129




      2,41331129










      asked Jan 19 at 0:51









      spencerchadspencerchad

      82




      82






















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          $begingroup$

          You cannot isolate $x$ and you will need some numerical method.



          If I had to do it, I would define $y=(1+mx)$ to make
          $$delta_f = delta_S-(delta_S-delta_o)expleft[-yfrac{It}{V}right]$$
          $$delta_S =frac{delta_{in}+mxdelta^*}{1+mx}=frac{delta_{in}-delta^*+ydelta^*}{y}=delta^*+frac{delta_{in}-delta^*}y$$ Use Newton method.



          In fact, I suppose that there could be an "explicit" solution in terms of the generalized Lambert function (have a look at equation $(4)$ in the paper).






          share|cite|improve this answer









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            $begingroup$

            You cannot isolate $x$ and you will need some numerical method.



            If I had to do it, I would define $y=(1+mx)$ to make
            $$delta_f = delta_S-(delta_S-delta_o)expleft[-yfrac{It}{V}right]$$
            $$delta_S =frac{delta_{in}+mxdelta^*}{1+mx}=frac{delta_{in}-delta^*+ydelta^*}{y}=delta^*+frac{delta_{in}-delta^*}y$$ Use Newton method.



            In fact, I suppose that there could be an "explicit" solution in terms of the generalized Lambert function (have a look at equation $(4)$ in the paper).






            share|cite|improve this answer









            $endgroup$


















              0












              $begingroup$

              You cannot isolate $x$ and you will need some numerical method.



              If I had to do it, I would define $y=(1+mx)$ to make
              $$delta_f = delta_S-(delta_S-delta_o)expleft[-yfrac{It}{V}right]$$
              $$delta_S =frac{delta_{in}+mxdelta^*}{1+mx}=frac{delta_{in}-delta^*+ydelta^*}{y}=delta^*+frac{delta_{in}-delta^*}y$$ Use Newton method.



              In fact, I suppose that there could be an "explicit" solution in terms of the generalized Lambert function (have a look at equation $(4)$ in the paper).






              share|cite|improve this answer









              $endgroup$
















                0












                0








                0





                $begingroup$

                You cannot isolate $x$ and you will need some numerical method.



                If I had to do it, I would define $y=(1+mx)$ to make
                $$delta_f = delta_S-(delta_S-delta_o)expleft[-yfrac{It}{V}right]$$
                $$delta_S =frac{delta_{in}+mxdelta^*}{1+mx}=frac{delta_{in}-delta^*+ydelta^*}{y}=delta^*+frac{delta_{in}-delta^*}y$$ Use Newton method.



                In fact, I suppose that there could be an "explicit" solution in terms of the generalized Lambert function (have a look at equation $(4)$ in the paper).






                share|cite|improve this answer









                $endgroup$



                You cannot isolate $x$ and you will need some numerical method.



                If I had to do it, I would define $y=(1+mx)$ to make
                $$delta_f = delta_S-(delta_S-delta_o)expleft[-yfrac{It}{V}right]$$
                $$delta_S =frac{delta_{in}+mxdelta^*}{1+mx}=frac{delta_{in}-delta^*+ydelta^*}{y}=delta^*+frac{delta_{in}-delta^*}y$$ Use Newton method.



                In fact, I suppose that there could be an "explicit" solution in terms of the generalized Lambert function (have a look at equation $(4)$ in the paper).







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Jan 19 at 4:18









                Claude LeiboviciClaude Leibovici

                123k1157134




                123k1157134






























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