dsolve(diff(X,t) not working for 3x3 matrix

Question

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the following code not working for 3x3 matrix , can only work for 2x2 , please help what is the error for solving 3 x3 ?

A=[ -0.12 0.05 0.05 ;0.1 -0.1 0; 0.02 0.05 -0.05 ]
syms x
syms x(t) y(t);
X = [x; y; b];
b = 0;
[Sx, Sy, Sz] = dsolve(diff(X,t) == A*X + b)

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Answer 1

Walter Roberson 2021-9-28

0 个投票

A=[ -0.12 0.05 0.05 ;0.1 -0.1 0; 0.02 0.05 -0.05 ]

A = 3×3

-0.1200 0.0500 0.0500 0.1000 -0.1000 0 0.0200 0.0500 -0.0500

syms x

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

b = 0;

X = [x; y; z];

eqn = diff(X,t) == A*X + b

eqn(t) =

[Sx, Sy, Sz] = dsolve(eqn)

Sx =

Sy =

Sz =

chen tianle 2021-9-28

hi can got it , but how you change your answer to this style? i feel is better to see and read ..

my is only one line , how change to your format in matlab ?

Walter Roberson 2021-9-28

I ran the code right here in MATLAB Answers, which uses Livescript . Livescript automatically formats symbolic expressions.