unable to find symbolic solution

Question

IVAN DONATI 2021-2-27

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/757914-unable-to-find-symbolic-solution

回答： Utkarsh Belwal 2021-3-2

clear all
syms Pb(t) ron roff ka kl eta xs(t) kc nc xc(t) vu nm Fm
ode1=diff(Pb)==(1-ron)*Pb-Pb*roff
ode2=(ka+kl)*eta*diff(xs)+ka*kl*xs==ka*(kc*nc*Pb*(xc-xs))+eta*diff(kc*nc*Pb*(xc-xs))
ode3=diff(xc)==Pb*(vu*(1-((kc*nc*Pb*(xc-xs))/(nm*Fm))))+(1-Pb)*diff(xs)
odes=[ode1;ode2;ode3]
[PbSol,xs,xc]=dsolve(odes)

error message: unable to find symbolic solution

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Answer 1

Utkarsh Belwal 2021-3-2

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/757914-unable-to-find-symbolic-solution#answer_636781

Hi IVAN,

If dsolve cannot find an explicit solution of a differential equation analytically, then it returns an empty symbolic array. You can solve the differential equation by using MATLAB® numerical solver, such as ode45. For more information, see Solve a Second-Order Differential Equation Numerically.

Also refer to this MATLAB answer: https://www.mathworks.com/matlabcentral/answers/604369-unable-to-find-symbolic-solution-warning

Thanks,

Utkarsh