Question: How to verify the solution of PDEs?


 

``

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restart:

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with(PDEtools):

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with(LinearAlgebra):

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alias(f=f(x,t),g=g(x,t));

f, g

(1)
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> 

 

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eq1:=diff(f,x)=-I*eta*f +I*exp(-I*t)*g;

diff(f, x) = -I*eta*f+I*exp(-I*t)*g

(2)
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eq2:=diff(g,x)=-I*eta*g +I*exp(I*t)*f;

diff(g, x) = -I*eta*g+I*exp(I*t)*f

(3)
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eq3:=diff(f,t)=(I*eta^2-I/2)*f +I*eta*exp(-I*t)*g;

diff(f, t) = (I*eta^2-(1/2)*I)*f+I*eta*exp(-I*t)*g

(4)
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eq4:=diff(g,t)=(-I*eta^2+I/2)*g +I*eta*exp(I*t)*f;

diff(g, t) = (-I*eta^2+(1/2)*I)*g+I*eta*exp(I*t)*f

(5)
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#### The solution of (2)-(5) is

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eq5:=f=I*(c1*exp(A)-c2*exp(-A))*exp(-i*t/2);

f = I*(exp(A)*c1-c2*exp(-A))*exp(-(1/2)*i*t)

(6)
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eq6:=g=(c2*exp(A)-c1*exp(-A))*exp(i*t/2);

g = (c2*exp(A)-c1*exp(-A))*exp((1/2)*i*t)

(7)
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#### where

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c1=sqrt(h-sqrt(h^2-1))/sqrt(h^2-1);c2=sqrt(h+sqrt(h^2-1))/sqrt(h^2-1);A=sqrt(h^2-1)*(x+I*h*t);

c1 = (h-(h^2-1)^(1/2))^(1/2)/(h^2-1)^(1/2)

 

c2 = (h+(h^2-1)^(1/2))^(1/2)/(h^2-1)^(1/2)

 

A = (h^2-1)^(1/2)*(x+I*h*t)

(8)
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#### How to verify (6) and (7) is the solution of (2)-(5)?

``


 

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