Solving the Diff.Eq. to Find v(x,p) and u(0,t)

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The discussion focuses on solving the differential equations for the functions v(x,p) and u(0,t) based on the given conditions. The equations include the second-order partial differential equation d²u/dx² = du/dt, with boundary conditions u(x,0) = 0 and d/dx u(0,t) = -1. The relationship v(x,p) is defined as an integral involving u(x,t) and the exponential function. The participants debate the validity of the initial conditions and their implications for the solution.

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Gekko
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u(x,t) defined for x>0 t>0
d2u/dx2=du/dt

Conditions:
u(x,0)=0
d/dx u(0,t)=-1
u(x,t) tends to 0 as x tends to infinity
d2v/dx2 =pv
d/dx v(0,p) =-1/p

v(x,p)=integral(0 to inf) exp(-pt) u(x,t) dt

How do we use this to find v(x,p) and u(0,t)?

For u(0,t) can we simply integrate wrt x d/dx u(0,t) = -x?


Thanks in advance
 
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I could be wrong, but isn't there something wrong with the conditions and the way you defined,

[tex]u(x,t)[/tex]

?

You said,

[tex]u(x,t)[/tex] [tex]\exists \forall x > 0, t>0[/tex]

but in the conditions you are somehow evaluating at,

[tex]t = 0[/tex]

[tex]u(x,0) = 0[/tex]
 
You are right. I saw this too but assumed something specific to the heat equation allows it. Or maybe we assume tending to? In any case this is how the question was stated
 

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