Question: Error in solving BVP using dsolve

January 25 2012 samantasubho 5
Maple 14

0

I tried to solve a non linear coupled boundary value problem in MAPLE using DSolve command. The code is :

alias(eta = e, theta = t)

Eq[1] := 5*(diff(F(e), `$`(e, 3)))+(m+3)*F(e)*(diff(F(e), `$`(e, 2)))-(2*m+1)*(diff(F(e), e))^2-(4*m+2)*H(e)-(m-2)*e*(diff(H(e), e)) = 0

Eq[2] := diff(H(e), e) = t(e)

Eq[3] := 5*(diff(t(e), `$`(e, 2)))/Pr-(m+3)*F(e)*(diff(t(e), e))-5*m*(diff(F(e), e))*t(e) = 0

BCs := [F(0), (D(F))(0), (D(F))(infinity), t(0)-1, t(infinity), H(infinity)]

pars := {Pr = 1, m = 0, infinity = 10}

for i to 3 do eq[i] := subs(pars, Eq[i]) end do

eqs := eq[1], eq[2], eq[3]

vars := F(eta), t(eta), H(eta)

bcs := op(subs(pars, BCs))

sol := dsolve({bcs, eqs}, {vars}, type = numeric, output = array([seq((1/10)*i, i = 0 .. 100)]))

MAPLE says: 

Error, (in dsolve/numeric/bvp) initial Newton iteration is not converging
The solution converges only when I give infinity= 3.8 However the values I get for infinity =3.8 is erroneous. I should get t'(0)=-0.38957, I am getting it as -0.050483.
How can I get rid of the problem?
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