Note that 'ODE' and 'PDE' are synonyms for 'DE'.
The variables used by the FunctionAdvisor command to create the calling sequence are local variables. Therefore, the previous examples does not depend on z.
To make the FunctionAdvisor command return results using global variables, pass the actual function call instead of the function name. In this case, for some special functions it is also necessary to indicate which variables are the "differential equation independent variables". For examples, consider the following.
Moreover, in the case of the DE topic, the arguments in the function call need not be a name, in which case the differential equation system for the composed function call given is computed. Compare the differential equation for JacobiTheta1 above and this other one taking as argument
Apart from optionally passing a list of independent variables, one can pass the dependent variable directly (it includes the information on the independent variables):