mgu

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9 years, 31 days

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These are questions asked by mgu

Hi, I am trying to compute the coefficient of a polynomial as follows:

a:=(1/11520)*(4518-4320*r^(2*n)-5760*_C1*n^4*r^2-97920*_C1*n^2*r^2-97920*_C1*n*r^2-40320*_C1*n^3*r^2+2020*r^6*n^3+1500*r^6*n^2-1440*r^(2*n+6)+60*r^8-2880*r^(2+2*n)-720*r^4-100*n^5-339*n^2+3018*r^2+4560*r^(2+2*n)*n-240*r^(2*n+4)*n^2-480*r^(2+2*n)*n^4+50*r^8*n-130*r^8*n^4-270*r^8*n^3-170*r^8*n^2-20*r^8*n^5+480*r^(2*n+6)*n+480*r^(2*n+6)*n^3-480*r^(2*n+6)*n^2-1680*r^(2+2*n)*n^3+160*n^5*r^6-102*n*r+320*r^2*n^5+1783*r^2*n^4...

I have an ODE to solve that looks like this: 

((diff(R(r), r, r, r, r))*r^4+3*(diff(R(r), r))*r-3*(diff(R(r), r, r))*r^2+2*(diff(R(r), r, r, r))*r^3-3*R(r)+4*R(r)*n+2*R(r)*n^2-4*(diff(R(r), r))*r*n+2*(diff(R(r), r))*r*n^2+4*(diff(R(r), r, r))*r^2*n-2*(diff(R(r), r, r))*r^2*n^2-4*R(r)*n^3+R(r)*n^4)/r^4 = (-108-1362*n+2122*n^2+2019*n^3-3032*n^4+401*n^7+1192*n^6-1033*n^5-25*n^9+6*n^10-180*n^8-4128*r^(n+3)*n^3+2304*r^(n+3)*n-576*r^(n+5)*n-760*n^6*r+575*n^5*r-244*n^7*r-2108*n^3*r-11616*r^(n+3...

Whoever is in charge of the question post management, please do not delete my question again without even notifying me. I have deleted the original post (which was a follow-up question to an old thread) so that my question can be viewed by others as a fresh post. Thank you!

Now to the question:

I am trying to solve a fourth-order ODE. Two of the boundary conditions are y(1)=0 and diff(y(x),x)=0 at x=1. The other two boundary conditions are y(x) and diff(y(x...

Hello all, I am wondering if anyone knows how to impose a finite value boundary condition to solve an ordinary differential equation? Specifically, suppose that the solution Maple obtains to an ordinary differential equation is y(x)=-2*x^2+C1*ln(x), C1 being a constant. Given that y(x) must be finite when x=0, then C1 has to be zero. Is there a way to implement this condition when setting up to solve the ODE in Maple, i.e. dsolve({ODE, ICs}, y(x), options)? Many thanks for your help!

I have the following lines of code:

 

W:=sum((k^(2*i))*sum((e^(j))*w[i,j](r,t),j=0..2),i=0..2);

P:=sum((k^(2*i+1))*sum((e^(j))*w[i,j](r,t),j=0..2),i=0..2);

for c from 0 to 2 do

  for d from 0 to 2 do

    rw[c,d]:=coeff(coeff((k/(2*r))*(diff(W,r)*diff(P,t)-diff(W,t)*diff(P,r)),k,2*c),e,d)

  end do

end do;

 

I mean to compute the coefficients in front of powers of e inside...

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