Error: Unable to find symbolic solution

2 ビュー (過去 30 日間)
Sabrina Garland
Sabrina Garland 2021 年 10 月 24 日
コメント済み: Sabrina Garland 2021 年 10 月 24 日
syms y(x)
ode= diff(y, x)== (-(5*y)/(2*x))/(1- ((1/(2*x))^2)*((y/(1-y))^(3/5)));
cond = y(1/2)==1/2;
ySol(x) = dsolve(ode, cond)
Warning: Unable to find symbolic solution
> In dsolve (line 209) ySol(x) = [ empty sym ]
What am I doing wrong? Please Help
  2 件のコメント
John D'Errico
John D'Errico 2021 年 10 月 24 日
編集済み: John D'Errico 2021 年 10 月 24 日
  1. Just because you want it to happen, symbolic solutions need not always exist for all problems. In fact, it is a vanishingly small number of problems with symbolic solutions.
  2. You can always use a numerical solver, perhaps ODE45 might be a good place to start. It will probably fail, because at y(1/2) == 1/2, there is a derivative singularity.
  3. Finally, sometimes a solution can be found by a clever transformation of the problem. This is why they pay the mathematicians the big bucks. (Yeah, right. Like that often happens.) Ok, the good mathematicians.
  4. The derivative singularity at y(1/2) == 1/2 may suggest a good transformation may exist, but you would need to be creative.
Ok, do you want something a bit more useful? If I had to guess, no explicit solution probably exists. The result is going to exist, if at all, as an implicit function.
Sabrina Garland
Sabrina Garland 2021 年 10 月 24 日

サインインしてコメントする。

回答 (0 件)

カテゴリ

Help Center および File ExchangeSymbolic Math Toolbox についてさらに検索

製品


リリース

R2021b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by