I can use functions- "sym()" and "syms()".

when I use functions-sym() and syms(), warning is that "Undefined function 'sym'/'syms' for input arguments of type 'char' ". why, and how I should modify it?

Answer 1

[Alexander]

The functions sym and syms are part of the Symbolic Math Toolbox. Are you sure that you have the Symbolic Math Toolbox installed?

Answer 2

[vx2008]

Ok，i know. I have install matlab 2012a and I head that it never include symbolic math toolbox but matlab 2012b does. "a doesn't and b does" always works, yes? why?

[Walter Roberson]

The Professional and Academic licenses do not include the Symbolic Math Toolbox; it is extra cost for those licenses for both the "a" and "b" releases.

The Student Version does include it, but does not install it by default. Historically, Student Versions have been released once per year, corresponding to the "a" release (with only one exception).