How to create symbol function matrix in matlab?

I need to solve a linear differential equations, such as diff(Y) = AY, Y(0) = Y0. Y \in R^n; So I need to generate a column of symbol function. I used the following code

clc;clear;
n = 7;
syms t V;
A = sym('A', [n 1]);
U = symfun(A,[t]);

However, as the result shows, the size of U is 1 by 1. I don't know what is wrong and how I can make it work.

I will appreciate your help a lot. Best,

Answer 1

[Star Strider]

The solution to your differential equation (assuming a constant ‘A’) is:

Y = expm(A*t)

You will likely have significant problems with it in the Symbolic Math Toolbox. I would deal with it only numerically.

[Andrew Newell]

Not quite - the correct answer is

Y = expm(A*t)*Y0

Answer 2

[Andrew Newell]

To get an n x n matrix, use

A = sym('A',n);

[Chuangchuang Sun]

I change the way to generate A but the resulting U is still shown to be 1 by 1. It seems it doesn't make a difference. Thanks!