## "unable to convert to an explicit first-order syst...

hi... I have a problem with dsolve.

"unable to convert to an explicit first-order system"

thanks

## Diff. Equation with boundary...

Hey. I have the following Diff. Equation:

diffeq := diff(y(t),t,t,t,t)+10*diff(y(t),t,t)+169*y(t)=0

and I have the conditions y(0) = 0, y'(0) = 1, and y(t) -> 0 for t -> infinity

I know how to do with the first two conditions, but how do you do it with a boundary? I've read the posts made earlier on here, but I can't seem to figure it out. I've tried:

dsolve({diffeq,y(0)=0,D(y)(0)=1,D(y)(infinity)=0},y(t))

Returns nothing.

Any help would be appreciated.

## suggestion on faster solving set of nonlinear ODEs...

#first_question :how can i solve set of nonlinear ODEs,faster or using any packages ?
#second_question :what can be some boundary conditions for this type of nonlinear ODEs? how many BCs are required for this set of nonlinear ODEs? ( to use numeric solution)

 > restart:with(DEtools):with(DifferentialAlgebra):
 > eq[1]:=diff(N(r),r\$2)+2/r*diff(N(r),r)+diff(phi(r),r)/phi(r)*diff(N(r),r)-mu^2/(32*phi(r))*N(r);
 (1)
 > eq[2]:=diff(phi(r),r\$2)+2/r*diff(phi(r),r)-1/2*diff(phi(r),r)^2/phi(r)-8*diff(N(r),r)^2/(omega*(1-2*G*M/r))*phi(r);
 (2)
 > dsolve({eq[1],eq[2]});

## How to solve BVP with singularities?...

Dear friends,

I have to solve the BVP of the following type:

(x-1)*y''(x)+y'(x)=1+x, y(0)=1, y(1)=1

Expressing the highest derivative (y''(x)), we get a singularity at x=1.

So, as recommended, the method bvp[middefer] (or bvp[midrich]) is used:

`dsolve({(x-1)*diff(y(x), x\$2)+diff(y(x),x) = 1+x, y(0)=0, y(1)=1}, type = numeric, method = bvp[middefer], y(x), 'output' = Array([seq(k/10, k=0..10)]), 'abserr'=1.0e-3, 'maxmesh'=100)`

Maple generates the following error:

Error, (in dsolve/numeric/bvp) unable to achieve requested accuracy of 0.10e-2 with maximum 100 point mesh (was able to get 0.82e3), consider increasing `maxmesh` or using larger `abserr`
But as I increase maxmesh, the achievable accuracy (reported in "(was able to get XXX)") decreases:

for

maxmesh = 200: 0.19e4

maxmesh = 500: 0.54e4

maxmesh = 1000: 0.12e5

maxmesh = 5000: 0.73e5

and so on.....

How to solve this equation with desirable accurancy and usage of Array as output?

## Error, (in fprintf) number expected for floating p...

hello...i have a problem with this program.

I want to save the result(y,u(y)) in a text or another format file, but I encounter with this error message:

Error, (in fprintf) number expected for floating point formatBVP.mw

restart:

A1:= 5.5:  n:= 0.59:  A2:= 11818.:  h0:= 0.402e-3:
L:= .1:  dpx := -11823.9:  uc:= 0.44e-2:

ODE:= (A3,y)->
(h0^(n+1)*L/sqrt(n)*(A1*exp(sqrt(n)*y/L)-A2*exp(-sqrt(n)*y/L))+dpx*y*h0^(n+1)+A3*(h0)^n)^(1/n)
;

 (1)

ODEINT:= proc(A3)
option remember;
local y;
evalf(Int(ODE(A3,y), y= 0..1, epsilon= 1e-7)) - uc
end proc:

ReINT:= proc(A3x, A3y)
Digits:= 15:
Re(ODEINT(A3x + I*A3y))
end proc:

ImINT:= subs(Re= Im, eval(ReINT)):

Digits:= 7:
a3:= fsolve([ReINT, ImINT]);

 (2)

A3:= Complex(a3[]);

 (3)

Solve as IVP:

Digits:= 15:
sol:= dsolve({diff(u(y),y) = ODE(A3,y), u(0)=0}, numeric, range=0..1,  output=listprocedure):

plots:-odeplot(
sol, [[y, Re(u(y))], [y, Im(u(y))]], y= 0..1,
legend= [real, imag], labels= [y, u(y)]
);

 >

thanks

## boundary conditions...

the program shows that the error please verify it sirprogram11.mw

## How do I solve a set of differential equations in ...

Hi, my dear friend,

i am solving 9 ODE with boundary conditionsNigam.mw

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Maple Worksheet - Error

Failed to load the worksheet

then i got this error

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

i dont know where i need to change.. could you help me..

## Numerical solution...

Hi Guyz

I have a problem with a numerical solution.

with the boundary conditions mentioned in the file we want to solve the differential equation numerically and find omega by using the shooting method

numshooting.mw

## differential equation...

i want to solve this equation,

y''(x)=5*exp(-10/y'(x)) on ]0,15[ with y(0)=0,y(15)=2

can any one help me ? thank you

## how do I remove the error "initial Newton iteratio...

Respected member!

Please help me in finding the solution of this problem....

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## intial value is not converging...

Dear please check once it showing an error program.mw as intial value is not conververging

## Fourth order problem showing use midpoint method...

Dear sir,

I tried to solve a fourth order problem. But I got the error message as better to use midpoint method. Can I know what is midpoint method and here I uploading the problem please verify it if I did anything mistake?program.mw

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## How do i fix the error"Newton iteration is not con...

Respected member!
Please help me to find the solution of attached problem.

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 (2)
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## Error, (in dsolve/numeric/BVPSolve) singularity en...

hi.

how i can dsolve this differential equations?

thanks