mjason

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15 years, 188 days

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These are replies submitted by mjason

thanks for the help. much appreciated

mj

thanks for the help. much appreciated

mj

thank you for your help. worked perfectly. exactly what i wanted. I have now got maple redefining F(eta) in a loop. If i now try to do a contourplot i just get the outcome:

contourplot(x*(-1/2*eta^3+3/2*eta),x = -10 .. 10,eta = -1 .. 1)

instead of a plot.

Here is the code i have used:

> restart;
> nmax:=14:
> Order:=nmax+1:
Start with the differential equation
> de:=diff(F(eta,R),eta$4)-R*(diff(F(eta,R),eta)*diff(F(eta,R),eta$2)-F(eta,R)*diff(F(eta,R),eta$3)):
Write in a series of powers of R
> series(eval(de,F(eta,R)=add(F[k](eta)*R^k,k=0..nmax)),R):
Extract the individual equations for each power upto R^5
> des:=[seq(coeff(%,R,k),k=0..nmax)]:
Define the boundary conditions
> bcs:=k->(F[k](-1)=`if`(k=0,-1,0),F[k](1)=`if`(k=0,1,0),D(F[k])(-1)=0,D(F[k])(1)=0):
Solve the boundary value problem for each power
> for k from 1 to nmax+1 do
>     F[k-1]:=unapply(rhs(dsolve({des[k],bcs(k-1)})),eta)
> end do:
> v[w]:=1:
> a:=1:
> contourplot(v[w]*x*F[0](eta),x=-10..10,eta=-a..a);

What is the reason it will plot in the first instance but not the second?

Thanks
 

thank you for your help. worked perfectly. exactly what i wanted. I have now got maple redefining F(eta) in a loop. If i now try to do a contourplot i just get the outcome:

contourplot(x*(-1/2*eta^3+3/2*eta),x = -10 .. 10,eta = -1 .. 1)

instead of a plot.

Here is the code i have used:

> restart;
> nmax:=14:
> Order:=nmax+1:
Start with the differential equation
> de:=diff(F(eta,R),eta$4)-R*(diff(F(eta,R),eta)*diff(F(eta,R),eta$2)-F(eta,R)*diff(F(eta,R),eta$3)):
Write in a series of powers of R
> series(eval(de,F(eta,R)=add(F[k](eta)*R^k,k=0..nmax)),R):
Extract the individual equations for each power upto R^5
> des:=[seq(coeff(%,R,k),k=0..nmax)]:
Define the boundary conditions
> bcs:=k->(F[k](-1)=`if`(k=0,-1,0),F[k](1)=`if`(k=0,1,0),D(F[k])(-1)=0,D(F[k])(1)=0):
Solve the boundary value problem for each power
> for k from 1 to nmax+1 do
>     F[k-1]:=unapply(rhs(dsolve({des[k],bcs(k-1)})),eta)
> end do:
> v[w]:=1:
> a:=1:
> contourplot(v[w]*x*F[0](eta),x=-10..10,eta=-a..a);

What is the reason it will plot in the first instance but not the second?

Thanks
 

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