PDE with terminal condition, Feynman-Kac












0












$begingroup$


I have the following PDE:
$$2u_t+9u_{xx}-2u_x=0$$
$$u(x,T)=e^x$$
and I get that
$$dX(s)=-dS+3dW(s)$$
$$X(t)=x$$



But how do I get the expected value of $e^x$?
I tried substituting $Y(s)=e^x$, but I get the wrong answer... The answer should be $u(x,t)=e^{(x+frac{7}{2}(T-t))}$.










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  • $begingroup$
    What is $X, S, W$ ?
    $endgroup$
    – Cesareo
    Dec 18 '18 at 20:42










  • $begingroup$
    Sorry, X is a stochastic process, W is a Wiener process and S is time
    $endgroup$
    – Natalie_94
    Dec 19 '18 at 10:34
















0












$begingroup$


I have the following PDE:
$$2u_t+9u_{xx}-2u_x=0$$
$$u(x,T)=e^x$$
and I get that
$$dX(s)=-dS+3dW(s)$$
$$X(t)=x$$



But how do I get the expected value of $e^x$?
I tried substituting $Y(s)=e^x$, but I get the wrong answer... The answer should be $u(x,t)=e^{(x+frac{7}{2}(T-t))}$.










share|cite|improve this question









$endgroup$












  • $begingroup$
    What is $X, S, W$ ?
    $endgroup$
    – Cesareo
    Dec 18 '18 at 20:42










  • $begingroup$
    Sorry, X is a stochastic process, W is a Wiener process and S is time
    $endgroup$
    – Natalie_94
    Dec 19 '18 at 10:34














0












0








0





$begingroup$


I have the following PDE:
$$2u_t+9u_{xx}-2u_x=0$$
$$u(x,T)=e^x$$
and I get that
$$dX(s)=-dS+3dW(s)$$
$$X(t)=x$$



But how do I get the expected value of $e^x$?
I tried substituting $Y(s)=e^x$, but I get the wrong answer... The answer should be $u(x,t)=e^{(x+frac{7}{2}(T-t))}$.










share|cite|improve this question









$endgroup$




I have the following PDE:
$$2u_t+9u_{xx}-2u_x=0$$
$$u(x,T)=e^x$$
and I get that
$$dX(s)=-dS+3dW(s)$$
$$X(t)=x$$



But how do I get the expected value of $e^x$?
I tried substituting $Y(s)=e^x$, but I get the wrong answer... The answer should be $u(x,t)=e^{(x+frac{7}{2}(T-t))}$.







pde stochastic-processes brownian-motion






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asked Dec 18 '18 at 19:53









Natalie_94Natalie_94

316




316












  • $begingroup$
    What is $X, S, W$ ?
    $endgroup$
    – Cesareo
    Dec 18 '18 at 20:42










  • $begingroup$
    Sorry, X is a stochastic process, W is a Wiener process and S is time
    $endgroup$
    – Natalie_94
    Dec 19 '18 at 10:34


















  • $begingroup$
    What is $X, S, W$ ?
    $endgroup$
    – Cesareo
    Dec 18 '18 at 20:42










  • $begingroup$
    Sorry, X is a stochastic process, W is a Wiener process and S is time
    $endgroup$
    – Natalie_94
    Dec 19 '18 at 10:34
















$begingroup$
What is $X, S, W$ ?
$endgroup$
– Cesareo
Dec 18 '18 at 20:42




$begingroup$
What is $X, S, W$ ?
$endgroup$
– Cesareo
Dec 18 '18 at 20:42












$begingroup$
Sorry, X is a stochastic process, W is a Wiener process and S is time
$endgroup$
– Natalie_94
Dec 19 '18 at 10:34




$begingroup$
Sorry, X is a stochastic process, W is a Wiener process and S is time
$endgroup$
– Natalie_94
Dec 19 '18 at 10:34










1 Answer
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0












$begingroup$

Hint:



Your SDE results in the following expression:



$X(T) = x - (T - t) + 3(W(T) - W(t))$



Now you just need to find $E[e^{X(T)}]$
Can you do that?



Hint2: MGF






share|cite|improve this answer









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    1 Answer
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    1 Answer
    1






    active

    oldest

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    active

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    0












    $begingroup$

    Hint:



    Your SDE results in the following expression:



    $X(T) = x - (T - t) + 3(W(T) - W(t))$



    Now you just need to find $E[e^{X(T)}]$
    Can you do that?



    Hint2: MGF






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      Hint:



      Your SDE results in the following expression:



      $X(T) = x - (T - t) + 3(W(T) - W(t))$



      Now you just need to find $E[e^{X(T)}]$
      Can you do that?



      Hint2: MGF






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        Hint:



        Your SDE results in the following expression:



        $X(T) = x - (T - t) + 3(W(T) - W(t))$



        Now you just need to find $E[e^{X(T)}]$
        Can you do that?



        Hint2: MGF






        share|cite|improve this answer









        $endgroup$



        Hint:



        Your SDE results in the following expression:



        $X(T) = x - (T - t) + 3(W(T) - W(t))$



        Now you just need to find $E[e^{X(T)}]$
        Can you do that?



        Hint2: MGF







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Dec 19 '18 at 15:43









        MakinaMakina

        1,1901316




        1,1901316






























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