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How to get rid of error about unconverge...

ehnber 10 Maple
dsolve numeric convergence
May 18 2016
0 2

How can i over come convergence error, i am unable to apply approxsoln appropriately and continouation as well. regards

N := 5;

-(1/2)*Pr*n*x*(diff(f(x), x))*(diff(theta(x), x))-(1/2)*Pr*(n+1)*f(x)*(diff(theta(x), x))-(1/2)*(n+1)*(diff(diff(theta(x), x), x))+Pr*gamma*((1/4)*(n^2-3*n+3)*x^2*(diff(f(x), x))*(diff(diff(f(x), x), x))*(diff(theta(x), x))+(1/4)*(2*n^2+5*n+3)*f(x)*(diff(f(x), x))*(diff(theta(x), x))+(1/4)*n(n+1)*x*f(x)*(diff(diff(f(x), x), x))*(diff(theta(x), x))+(1/4)*(2*n^2+3*n-3)*x*(diff(f(x), x))^2*(diff(theta(x), x))+(1/4)*(n-1)*x^2*(diff(diff(f(x), x), x))*(diff(theta(x), x))+(1/2)*n*(n+1)*x*f(x)*(diff(f(x), x))*(diff(diff(theta(x), x), x))+(1/4)*(n^2-1)*(diff(f(x), x))^2*(diff(theta(x), x))+(1/4)*(n+1)^2*f(x)^2*(diff(diff(theta(x), x), x))+(1/4)*(n-1)^2*x^2*(diff(f(x), x))^2*(diff(diff(theta(x), x), x))) = 0

 (1)

bc := (D(theta))(0) = -Bi*(1-theta(0)), theta(N) = 0, f(0) = 0, (D(f))(0) = 0, (D(f))(N) = 1;

(D(theta))(0) = -Bi*(1-theta(0)), theta(5) = 0, f(0) = 0, (D(f))(0) = 0, (D(f))(5) = 1

 (2)

a1 := dsolve(subs(beta = .1, n = .5, Pr = 10, gamma = .1, Bi = 50, {bc, eq1, eq2}), numeric, method = bvp[midrich], abserr = 10^(-8), output = array([seq(.1*i, i = 0 .. 10*N)]))

Error, (in dsolve/numeric/BVPSolve) initial Newton iteration is not converging

  

``

 

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How to fix this error? ...

ehnber 10 Maple
ode dsolve numeric
April 15 2016
0 1

I want to solve system of non linear odes numerically.

I encounter following error

Error, (in dsolve/numeric/bvp) cannot determine a suitable initial profile, please specify an approximate initial solution

how to correct it

regards

how can i correct the following error > ...

ehnber 10 Maple 13
error integration
November 18 2013
1 0

> restart; with(plots); with(LinearAlgebra); with(IntegrationTools); pde := rho(x)*(Diff(u(t, x), t, t))+lambda(x)*(Diff(u(t, x), t))-(Diff(P(x)*(Diff(u(t, x), x)), x))-Q(x)*u(t, x)+R(x);

> eq1 := int(pde*phi[i](x), x = -1 .. 1);

eq2 := expand(eq1);

> eq3 := applyop(u -> Parts(u, phi[i](x)) end proc, 3, eq2);

i get an error

Error, (in applyop) improper op or subscript selector

how to correct it??

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