symbol from string [2]

I have already posted about this ( http://www.mathworks.it/matlabcentral/answers/7220-symbol-from-string )

a='name'
syms (a)

this code generates a symbol called 'name'. If I write a function, I don't know the string before I use it, so how can I use the symbol 'name' (like symbol) into the function?

i.e

function [A]=f(a)
a='name';
syms (a)

c=cos(name);
s=sin(name);
A=c+s;

In the output I want a symbolic expression A=cos(name) + sin(name).

Thank you a lot for you answer. Pietro Rossi

Answer 1

[Walter Roberson]

I would try

function [A]=f(a)
%a='name';  %I presume this will be passed in
syms (a)

c=cos(a);
s=sin(a);
A=c+s;

[Pietro Rossi]

The function is:

function [A]=f(a)

syms (a)

c=cos(a);

s=sin(a);

A=c+s;

So, in the workspace I wrote:

a = 'nome';

A=f(a)

but Matlab sayd:

??? Undefined function or method 'cos' for input arguments of type 'char'.

Error in ==> fprova at 4

c=cos(a);

I tried in assign "syms name" before using f function:

syms nome

a = 'nome';

A=f(a)

:(

[Walter Roberson]

Ah, in that case,

function [A]=f(a)

as = syms (a)

c=cos(as);

s=sin(as);

A=c+s;

[Pietro Rossi]

Thanks so mush! The function run now! :)