MATLAB: Trouble with syms command: Symbolic Toolbox Test = 1

dsolveerror assignininvalid variable nameMATLABsymbolic functionssyms

I am having an issue using the syms command. According to the documentation,
 syms f(t) g(t)
should produce two symbolic functions, both which being functions of the symbolic variable t. However, I am getting the following error:
 Error using assignin
 Invalid variable name "f(t)" in ASSIGNIN.
 Error in syms (line 56)
       assignin('caller',varargin{i},sym(varargin{i}));
I checked to make sure that the symbolic toolbox was installed by entering:
 license('test','symbolic_toolbox')
which returned
 ans =
     1
I am trying to use the symbolic definitions of several functions as inputs into dsolve. Here is the operative part of my code:
    syms n8(t) n9(t) np(t)
    ode1 = diff(n8) == -n238*siga238*phi;
    ode2 = diff(n9) == n238*(siga238-sigf238)*phi - n239*siga239*phi;
    ode3 = diff(np) == 2*n238*sigf238*phi + 2*n239*sigf239*phi;
    odes = [ode1; ode2; ode3];
    n2380 = n8(0) == n238(i1-1);
    n2390 = n9(0) == n239(i1-1);
    nfp0 = np(0) == nfp(i1-1);

Best Answer

According to the Release Notes, the ability to create symbolic functions using that syntax was introduced in release R2012a. Are you using an older release? If so you will not be able to use that syntax.
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