dsolve - Unable to find explicit solution
조회 수: 2 (최근 30일)
이전 댓글 표시
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?
댓글 수: 0
채택된 답변
Walter Roberson
2018년 3월 7일
Nothing. It just does not have a closed form solution that can reasonably be found.
댓글 수: 0
추가 답변 (2개)
Jakub Jedrzejczyk
2018년 3월 7일
댓글 수: 8
Nenad Vujovic
2020년 1월 25일
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
2020년 1월 25일
That is the solution. Most integrals do not have closed form solutions.
Om Yadav
2020년 4월 24일
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?
댓글 수: 0
참고 항목
카테고리
Help Center 및 File Exchange에서 Equation Solving에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!