The findsym(M) function finds symbolic variables in M. The sequence of symbols are returned in alphabetical order.

The findsym(M,n) function finds the n symbolic variables in an expression nearest in alphabetical order to the letter x.

Symbolic constants like the imaginary unit and Pi are not considered variables, so they will not be returned from a call to findsym even when present in the given expression.

$\mathrm{with}\left(\mathrm{MTM}\right)\:$

$M≔\mathrm{Matrix}\left(2\,3\,'\mathrm{fill}'=a\left(x+y\right)\right)\:$

$\mathrm{findsym}\left(M\right)$

$\left[\begin{array}{ccc}a& x& y\end{array}\right]$

$\mathrm{findsym}\left(\mathrm{\alpha }+a+b\right)$

$\left[\begin{array}{ccc}a& \mathrm{\alpha }& b\end{array}\right]$

$\mathrm{findsym}\left(\cos \left(\mathrm{\alpha }\right)b\mathrm{x1}+14y\,2\right)$

$\left[\begin{array}{cc}\mathrm{x1}& y\end{array}\right]$

$\mathrm{findsym}\left(y\left(4+3\mathrm{I}\right)+6\right)$

$y$