dsolve - Unable to find explicit solution
2 visualizaciones (últimos 30 días)
Mostrar comentarios más antiguos
Jakub Jedrzejczyk
el 7 de Mzo. de 2018
Respondida: Om Yadav
el 24 de Abr. de 2020
Hi there! I'm trying to solve differetial equation:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/171047/image.jpeg)
Unfortunately result of code:
gamma = 1.4
P0 = 1
Pe = 9.4
R = 0.168
syms S P(t)
eqn = diff(P,t) == (3/R)*S*(Pe-P0)*((P/P0)^(1/gamma))*(1-((P0/P)^(1/gamma))*((Pe-P)/(Pe-P0)))^(2/3);
dsolve(eqn)
is:
Warning: Unable to find explicit solution. Returning implicit solution instead.
> In dsolve (line 208)
In Untitled (line 7)
ans =
1
1/root(z^6 + z^5 + z^4 + z^3 + z^2 + (5*z)/47 + 5/47, z, 1)^7
solve(int(42^(2/3)/(P^(5/7)*(5*P^(2/7) - 47/P^(5/7) + 42)^(2/3)), P, 'IgnoreSpecialCases', true, 'IgnoreAnalyticConstraints', true) - 150*S*t - C11 == 0, P)
What i'm doing wrong?
0 comentarios
Respuesta aceptada
Walter Roberson
el 7 de Mzo. de 2018
Nothing. It just does not have a closed form solution that can reasonably be found.
0 comentarios
Más respuestas (2)
Jakub Jedrzejczyk
el 7 de Mzo. de 2018
8 comentarios
Nenad Vujovic
el 25 de En. de 2020
Can someone solve this:
>> syms y(t);
dsolve('Dy=sin(t)*cos(t)+2-(y*cos(t))')
ans =
C5*exp(-sin(t)) + exp(-sin(t))*int((exp(sin(t))*(sin(2*t) + 4))/2, t, 'IgnoreAnalyticConstraints', true)
Walter Roberson
el 25 de En. de 2020
That is the solution. Most integrals do not have closed form solutions.
Om Yadav
el 24 de Abr. de 2020
We got it very well that closed formula for my problem does not exist. The question is, how to get a numerical solution using dsolve?
0 comentarios
Ver también
Categorías
Más información sobre Equation Solving en Help Center y File Exchange.
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!