solving for a variable that exist inside as well as outside of natural log or exponent











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can the following equation be solved for K analytically? If not, then what other approaches I could try out?



K*ln[(C2-K)/(C1-K)] = -(F/V)*t


The original equation was:



C2 = K + (C1-K)*exp(-(F/KV)*t)









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  • 1




    Do not expect this to have a nice solution. Look into root-finding (en.wikipedia.org/wiki/Root-finding_algorithm) instead.
    – parsiad
    Jan 25 '16 at 2:13










  • You would have to use the Lambert W function to find it in closed terms.
    – Simply Beautiful Art
    Jan 27 '16 at 22:49










  • You can call $-F/V*t$ another variable so that it doesn't look as messy.
    – Simply Beautiful Art
    Jan 27 '16 at 22:50















up vote
0
down vote

favorite












can the following equation be solved for K analytically? If not, then what other approaches I could try out?



K*ln[(C2-K)/(C1-K)] = -(F/V)*t


The original equation was:



C2 = K + (C1-K)*exp(-(F/KV)*t)









share|cite|improve this question




















  • 1




    Do not expect this to have a nice solution. Look into root-finding (en.wikipedia.org/wiki/Root-finding_algorithm) instead.
    – parsiad
    Jan 25 '16 at 2:13










  • You would have to use the Lambert W function to find it in closed terms.
    – Simply Beautiful Art
    Jan 27 '16 at 22:49










  • You can call $-F/V*t$ another variable so that it doesn't look as messy.
    – Simply Beautiful Art
    Jan 27 '16 at 22:50













up vote
0
down vote

favorite









up vote
0
down vote

favorite











can the following equation be solved for K analytically? If not, then what other approaches I could try out?



K*ln[(C2-K)/(C1-K)] = -(F/V)*t


The original equation was:



C2 = K + (C1-K)*exp(-(F/KV)*t)









share|cite|improve this question















can the following equation be solved for K analytically? If not, then what other approaches I could try out?



K*ln[(C2-K)/(C1-K)] = -(F/V)*t


The original equation was:



C2 = K + (C1-K)*exp(-(F/KV)*t)






logarithms exponential-function






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 25 '16 at 2:03

























asked Jan 25 '16 at 1:34









ToNoY

13315




13315








  • 1




    Do not expect this to have a nice solution. Look into root-finding (en.wikipedia.org/wiki/Root-finding_algorithm) instead.
    – parsiad
    Jan 25 '16 at 2:13










  • You would have to use the Lambert W function to find it in closed terms.
    – Simply Beautiful Art
    Jan 27 '16 at 22:49










  • You can call $-F/V*t$ another variable so that it doesn't look as messy.
    – Simply Beautiful Art
    Jan 27 '16 at 22:50














  • 1




    Do not expect this to have a nice solution. Look into root-finding (en.wikipedia.org/wiki/Root-finding_algorithm) instead.
    – parsiad
    Jan 25 '16 at 2:13










  • You would have to use the Lambert W function to find it in closed terms.
    – Simply Beautiful Art
    Jan 27 '16 at 22:49










  • You can call $-F/V*t$ another variable so that it doesn't look as messy.
    – Simply Beautiful Art
    Jan 27 '16 at 22:50








1




1




Do not expect this to have a nice solution. Look into root-finding (en.wikipedia.org/wiki/Root-finding_algorithm) instead.
– parsiad
Jan 25 '16 at 2:13




Do not expect this to have a nice solution. Look into root-finding (en.wikipedia.org/wiki/Root-finding_algorithm) instead.
– parsiad
Jan 25 '16 at 2:13












You would have to use the Lambert W function to find it in closed terms.
– Simply Beautiful Art
Jan 27 '16 at 22:49




You would have to use the Lambert W function to find it in closed terms.
– Simply Beautiful Art
Jan 27 '16 at 22:49












You can call $-F/V*t$ another variable so that it doesn't look as messy.
– Simply Beautiful Art
Jan 27 '16 at 22:50




You can call $-F/V*t$ another variable so that it doesn't look as messy.
– Simply Beautiful Art
Jan 27 '16 at 22:50










1 Answer
1






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up vote
0
down vote













To start, I point out a few things.



A) You could simply solve for $K$ using Lagrange Inversion Theorem.



B) You could try to solve for $K$ in closed form using the Lambert W function.



As for A), you will need to understand calculus.



As for B), I know it won't work, it only works to solve some problems of this type.



I can solve the following:



$$Kln(K)=A$$



$$K^K=e^A$$



$$K=e^{W(A)}$$



Solution here.
However, a problem like:



$$Kln(K+a)=A$$



Is unsolvable.



Yours is also unsolvable.






share|cite|improve this answer





















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    1 Answer
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    1 Answer
    1






    active

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    active

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    up vote
    0
    down vote













    To start, I point out a few things.



    A) You could simply solve for $K$ using Lagrange Inversion Theorem.



    B) You could try to solve for $K$ in closed form using the Lambert W function.



    As for A), you will need to understand calculus.



    As for B), I know it won't work, it only works to solve some problems of this type.



    I can solve the following:



    $$Kln(K)=A$$



    $$K^K=e^A$$



    $$K=e^{W(A)}$$



    Solution here.
    However, a problem like:



    $$Kln(K+a)=A$$



    Is unsolvable.



    Yours is also unsolvable.






    share|cite|improve this answer

























      up vote
      0
      down vote













      To start, I point out a few things.



      A) You could simply solve for $K$ using Lagrange Inversion Theorem.



      B) You could try to solve for $K$ in closed form using the Lambert W function.



      As for A), you will need to understand calculus.



      As for B), I know it won't work, it only works to solve some problems of this type.



      I can solve the following:



      $$Kln(K)=A$$



      $$K^K=e^A$$



      $$K=e^{W(A)}$$



      Solution here.
      However, a problem like:



      $$Kln(K+a)=A$$



      Is unsolvable.



      Yours is also unsolvable.






      share|cite|improve this answer























        up vote
        0
        down vote










        up vote
        0
        down vote









        To start, I point out a few things.



        A) You could simply solve for $K$ using Lagrange Inversion Theorem.



        B) You could try to solve for $K$ in closed form using the Lambert W function.



        As for A), you will need to understand calculus.



        As for B), I know it won't work, it only works to solve some problems of this type.



        I can solve the following:



        $$Kln(K)=A$$



        $$K^K=e^A$$



        $$K=e^{W(A)}$$



        Solution here.
        However, a problem like:



        $$Kln(K+a)=A$$



        Is unsolvable.



        Yours is also unsolvable.






        share|cite|improve this answer












        To start, I point out a few things.



        A) You could simply solve for $K$ using Lagrange Inversion Theorem.



        B) You could try to solve for $K$ in closed form using the Lambert W function.



        As for A), you will need to understand calculus.



        As for B), I know it won't work, it only works to solve some problems of this type.



        I can solve the following:



        $$Kln(K)=A$$



        $$K^K=e^A$$



        $$K=e^{W(A)}$$



        Solution here.
        However, a problem like:



        $$Kln(K+a)=A$$



        Is unsolvable.



        Yours is also unsolvable.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 27 '16 at 22:56









        Simply Beautiful Art

        50.1k577181




        50.1k577181






























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