Error using dsolve, System of differential Equations

Question

Devansh Saxena 2019-9-10

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/479772-error-using-dsolve-system-of-differential-equations

回答： Vidip 2024-4-12

Error:

Warning: Unable to find explicit solution.

> In dsolve (line 201)

In Nose_Differentiation (line 18)

Error using sym/subsindex (line 814)

Invalid indexing or function definition. Indexing must follow MATLAB indexing. Function

arguments must be symbolic variables, and function body must be sym expression.

Error in Nose_Differentiation (line 18)

[xSol(t), ySol(t), zSol(t)] = dsolve(odes,conds);

Code:

clear;

syms x(t) y(t) z(t);

cond1 = x(0) == 0;

cond2 = y(0) == 2;

cond3 = z(0) == 0;

conds = [cond1; cond2; cond3];

ode1 = diff(x) == y;

ode2 = diff(y) == -1*x + y*z;

ode3 = diff(z) == x*x - 4*y*y - 1;

odes = [ode1; ode2; ode3];

[xSol(t), ySol(t), zSol(t)] = dsolve(odes,conds);

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Answer 1

Vidip 2024-4-12

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/479772-error-using-dsolve-system-of-differential-equations#answer_1440156

The error you're encountering arises from attempting to assign the output of ‘dsolve’ directly to function handles in a way that MATLAB doesn't support. When solving for multiple functions, ‘dsolve’ returns a structure by default. Alternatively, you can assign solutions to functions or variables directly by explicitly specifying the outputs as a vector where the ‘dsolve’ function only expects the equations to be passed as an input argument. You can refer to the below documentation link to get more information-