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

Hi

I have two equations as follows:

The goal is finding the parameter 'phi'. This parameter is a positive real numeric constant.

I uploaded two files that they are included two methods to solve the problem.

1.mw

2.mw

Is method in the first file mathematically logical? If it is a correct method, why the command fsolve dosent work?

In file 2, we have 2 equations with further indeterminantes. The constant 'phi' must be minimum possible amount. How we can use the commands like the Minimize in Optimization? Please hint me.

Moreover, if there is a method to solve this problem please help me to know.

Thank you very much 

 

 

Hi, my dear friend,

i am solving 9 ODE with boundary conditionsNigam.mw

Eq1 := 2.*F1(eta)+diff(H1(eta), eta) = 0

2.*F1(eta)+diff(H1(eta), eta) = 0

(1)

Eq2 := F1(eta)^2-G1(eta)^2+(diff(F1(eta), eta))*H1(eta)-(diff(F1(eta), eta, eta)) = 0

F1(eta)^2-G1(eta)^2+(diff(F1(eta), eta))*H1(eta)-(diff(diff(F1(eta), eta), eta)) = 0

(2)

Eq3 := 2*F1(eta)*G1(eta)+H1(eta)*(diff(G1(eta), eta))-(diff(G1(eta), eta, eta)) = 0

2*F1(eta)*G1(eta)+H1(eta)*(diff(G1(eta), eta))-(diff(diff(G1(eta), eta), eta)) = 0

(3)

Eq4 := 4*F1(eta)*F3(eta)+H3(eta)*(diff(F1(eta), eta))+H1(eta)*(diff(F3(eta), eta))-2*G1(eta)*G3(eta)-2.*F1(eta)^2-1.5*H1(eta)-(diff(F3(eta), eta, eta)) = 0

4*F1(eta)*F3(eta)+H3(eta)*(diff(F1(eta), eta))+H1(eta)*(diff(F3(eta), eta))-2*G1(eta)*G3(eta)-2.*F1(eta)^2-1.5*H1(eta)-(diff(diff(F3(eta), eta), eta)) = 0

(4)

Eq5 := 2*F3(eta)*G1(eta)+4*F1(eta)*G3(eta)+H3(eta)*(diff(G1(eta), eta))-H1(eta)*(diff(G3(eta), eta))-2*F1(eta)*G1(eta)-1.5*H1(eta)*(diff(G1(eta), eta))-(diff(G3(eta), eta, eta)) = 0

2*F3(eta)*G1(eta)+4*F1(eta)*G3(eta)+H3(eta)*(diff(G1(eta), eta))-H1(eta)*(diff(G3(eta), eta))-2*F1(eta)*G1(eta)-1.5*H1(eta)*(diff(G1(eta), eta))-(diff(diff(G3(eta), eta), eta)) = 0

(5)

Eq6 := 4.*F3(eta)+diff(H3(eta), eta) = 0

4.*F3(eta)+diff(H3(eta), eta) = 0

(6)

Eq7 := 6*F1(eta)*F5(eta)-6*F1(eta)*F3(eta)+3.*F3(eta)^2+H1(eta)*(diff(F5(eta), eta))+H3(eta)*(diff(F3(eta), eta))+H5(eta)*(diff(F1(eta), eta))-1.5*(H1(eta)*(diff(F3(eta), eta))+H3(eta)*(diff(F1(eta), eta)))-G3(eta)^2-2*G1(eta)*G5(eta)-(diff(F5(eta), eta, eta)) = 0

6*F1(eta)*F5(eta)-6*F1(eta)*F3(eta)+3.*F3(eta)^2+H1(eta)*(diff(F5(eta), eta))+H3(eta)*(diff(F3(eta), eta))+H5(eta)*(diff(F1(eta), eta))-1.5*H1(eta)*(diff(F3(eta), eta))-1.5*H3(eta)*(diff(F1(eta), eta))-G3(eta)^2-2*G1(eta)*G5(eta)-(diff(diff(F5(eta), eta), eta)) = 0

(7)

Eq8 := 6*G5(eta)*F1(eta)+2*G1(eta)*F5(eta)+4*G3(eta)*F3(eta)-4*F1(eta)*G3(eta)-2*F3(eta)*G1(eta)+H1(eta)*(diff(G5(eta), eta))-1.5*(H1(eta)*(diff(G3(eta), eta))+H3(eta)*(diff(G1(eta), eta)))+H3(eta)*(diff(G3(eta), eta))+H5(eta)*(diff(G1(eta), eta))-(diff(G5(eta), eta, eta)) = 0

6*G5(eta)*F1(eta)+2*G1(eta)*F5(eta)+4*G3(eta)*F3(eta)-4*F1(eta)*G3(eta)-2*F3(eta)*G1(eta)+H1(eta)*(diff(G5(eta), eta))-1.5*H1(eta)*(diff(G3(eta), eta))-1.5*H3(eta)*(diff(G1(eta), eta))+H3(eta)*(diff(G3(eta), eta))+H5(eta)*(diff(G1(eta), eta))-(diff(diff(G5(eta), eta), eta)) = 0

(8)

Eq9 := 6.*F5(eta)+F3(eta)+diff(H5(eta), eta) = 0

6.*F5(eta)+F3(eta)+diff(H5(eta), eta) = 0

(9)

bcs1 := F1(0) = 0, F3(0) = 0, F5(0) = 0

F1(0) = 0, F3(0) = 0, F5(0) = 0

(10)

bcs2 := G1(0) = 1, G3(0) = 0, G5(0) = 0

G1(0) = 1, G3(0) = 0, G5(0) = 0

(11)

bcs3 := H1(0) = 0, H3(0) = 0, H5(0) = 0

H1(0) = 0, H3(0) = 0, H5(0) = 0

(12)

bcs4 := F1(10) = 0, F3(10) = 0, F5(10) = 0

F1(10) = 0, F3(10) = 0, F5(10) = 0

(13)

bcs5 := G1(10) = 0, G3(10) = 0, G5(10) = 0

G1(10) = 0, G3(10) = 0, G5(10) = 0

(14)

R := dsolve(eval({Eq1, Eq2, Eq3, Eq4, Eq5, Eq6, Eq7, Eq8, Eq9, bcs1, bcs2, bcs3, bcs4, bcs5}), [F1(eta), F3(eta), F5(eta), G1(eta), G3(eta), G5(eta), H1(eta), H3(eta), H5(eta)], numeric, output = listprocedure)

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

 

``


Maple Worksheet - Error

Failed to load the worksheet 

Download Nigam.mwNigam.mw

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..

sol := dsolve(diff(ln(y(x)),x) = y(x)^(1/(1-y(x))), y(x));
x-Intat(_a^(-(-2+_a)/(-1+_a)), _a = y(x))+_C1 = 0
 

the solution is not y(x) = , but y(x) at the right hand side

Int(exp(LambertW(1/(-1+x))*(-1+x)), x)+1
 
x-Intat(1/exp((-1+_a)*LambertW(1/(-1+_a))), _a = y(x))-_C1 = 0
 
i use dsolve two equations, get two possible results,
how to evaluate these functions or how to use these functions?
mas := proc(f)
return ln(diff(rhs(subs(_C1=0,dsolve(diff(y(x),x) = f))), x$2));
end proc:
mas(exp(x));
mas(mas(exp(x)));
mas(x^2);
mas(x^2+x^3);
 
when i hard code x, there is no problem in above code.
but when i op to get variable x and run below, it do not have problem when run line by line, but it has problem when run in
procedure
Error, (in mas) invalid input: diff received exp(x), which is not valid for its 2nd argument
 
mas := proc(f)
local martin:
martin := op(f):
return ln(diff(rhs(subs(_C1=0,dsolve(diff(y(martin),martin) = f))), martin$2));
end proc:
 
mas(exp(x));
mas(mas(exp(x)));
mas(x^2);
mas(x^2+x^3);

Hi, There is a problem in solving ODE using dsolve/numeric code. You people would like to help me in resolving the error, here is in attached file,

Latif_paper.mw

I have a differential equation which it seems not be solvable. can anyone help me to solve?

Thank you

difeq.mw


 

restart

eq := diff(y(t), t, t)+9*y(t) = Dirac(t)

diff(diff(y(t), t), t)+9*y(t) = Dirac(t)

(1)

with(inttrans):

icon := y(0) = 0, (D(y))(0) = 0;

y(0) = 0, (D(y))(0) = 0

(2)

dsolve({eq, icon}, y(t), method = laplace);

y(t) = (1/3)*sin(3*t)

(3)

dsolve({eq, icon}, y(t));

y(t) = (1/3)*(Heaviside(t)-1/2)*sin(3*t)

(4)

``


 

Download Dirac_for_Primes.mw

Hi! I have the system of differential equations

restart; with(plots); with(DEtools);

a := 1;

deq1 := u(s)*(diff(varphi(s), s, s))+2*(diff(u(s), s))*(diff(varphi(s), s))+sin(varphi(s)) = 0;

deq2 := diff(u(s), s, s)-u(s)*(diff(varphi(s), s))^2-cos(varphi(s))+a*(u(s)-1) = 0;

sol := dsolve({deq1, deq2, u(0) = 1, varphi(0) = (1/4)*Pi, (D(u))(0) = 0, (D(varphi))(0) = 0}, {u(s), varphi(s)}, numeric)

 

which is perfectly solved, but I need to convert it to Cartesian coordinates and draw a plot, so what I tried is

x := u(s)*sin(varphi(s));

y := -u(s)*cos(varphi(s));

plot([x, y, s = 0 .. 20])

 

But I'm getting an error "Warning, expecting only range variable s in expressions [u(s)*sin(varphi(s)), -u(s)*cos(varphi(s))] to be plotted but found names [u, varphi]"

I don't know why is this happens if I have a solution. For example, I can get solution for 2 seconds:

sol(2)

[s = 2., u(s) = 2.33095721668252, diff(u(s), s) = 1.02513293353371, varphi(s) = .213677391510693, diff(varphi(s), s) = -.242430995691885]

 

Hi,

 

I have a problem of having a problem to solve the following equation with the this error. I found out that it might be due to that I have a differential that is squared and maple could not calculate it as after square root it will have positive and negative. May I know how to overcome this other than changing my equations?

ODE_summarize.mw
 

restart; with(DEtools)

````

sol1 := alpha*(diff(f(y), y, y, y)) = -(1/4)*f(y)*(diff(f(y), y, y))*n+(1/2)*(diff(f(y), y))^2*n-(3/4)*f(y)*(diff(f(y), y, y))+(1/2)*(diff(f(y), y))^2-g(y), diff(g(y), y, y) = -(1/4)*P[r](f(y)*(diff(g(y), y))*n-4*n*(diff(f(y), y))*g(y)+3*f(y)*(diff(g(y), y)))

alpha*(diff(diff(diff(f(y), y), y), y)) = -(1/4)*f(y)*(diff(diff(f(y), y), y))*n+(1/2)*(diff(f(y), y))^2*n-(3/4)*f(y)*(diff(diff(f(y), y), y))+(1/2)*(diff(f(y), y))^2-g(y), diff(diff(g(y), y), y) = -(1/4)*P[r](f(y)*(diff(g(y), y))*n-4*n*(diff(f(y), y))*g(y)+3*f(y)*(diff(g(y), y)))

(1)

bc := (D(f))(y)

(D(f))(y)

(2)

gg := convert(bc, diff)

diff(f(y), y)

(3)

gg1 := limit(gg, y = infinity)

limit(diff(f(y), y), y = infinity)

(4)

gg2 := convert(gg1, D) = 0

limit((D(f))(y), y = infinity) = 0

(5)

gg2

(D(f))(y) = 0

(6)

bc1 := eval(f(y), y = 0) = 0, eval((D(f))(y), y = 0) = 0, convert(gg1, D) = 0, limit(g(y), y = infinity) = 0, eval(g(y), y = 0) = 1

f(0) = 0, (D(f))(0) = 0, limit((D(f))(y), y = infinity) = 0, limit(g(y), y = infinity) = 0, g(0) = 1

(7)

``

odesub1 := eval(eval(sol1, n = .6), P[r] = 0)

alpha*(diff(diff(diff(f(y), y), y), y)) = -.9000000000*f(y)*(diff(diff(f(y), y), y))+.8000000000*(diff(f(y), y))^2-g(y), diff(diff(g(y), y), y) = 0

(8)

sol2 := dsolve({bc1, odesub1}, numeric, [f(y), g(y)], output = operator, continuation = alpha, initmesh = 2400, method = bvp[midrich])

Error, (in dsolve/numeric/bvp/convertsys) unable to convert to an explicit first-order system

 

``


 

 

 

 

 

 

 

 

 

 

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

Hi guys ,

Actually i dont know how to solve the following complicated differential equations by numerical methods ,

numerical.mw

 

Thank you for your attention to this matter

I want to solve the system of differential equations
sys :=
  diff(x(t,s),t) = y(t,s),
  diff(y(t,s),t) + x(t,s) = 0;

subject to the initial condition
ic := x(0,s) = a(s),
      y(0,s) = b(s);

where a(s) and b(s) are given.

This looks like a system of PDEs but actually it is a system
of ODEs because there are no derivatives with respect to s.
It is easy to obtain the solution by hand:

x(t,s) = b(s)*sin(t) + a(s)*cos(t)
y(t,s) = b(s)*cos(t) - a(s)*sin(t)

I don't know how to get this in Maple, either through dsolve()
or pdsolve().

Actually both dsolve({sys}) and pdsolve({sys}) do return
the correct general solution, however dsolve({sys, ic})
or pdsolve({sys, ic}) produce no output.  Is there a trick
to make the latter work?

 

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