* iunvfunc = a string vector of the inverse of these functions
Output
* nothing: string vectors are stored in a database
DESCRIPTION
Saves into the database functions.dat a string vector of functions and a string of the inverse of these functions.
EXAMPLE
define_func2inv(['log';'exp';'sin';'cos';'log10';'sqrt'],['exp';'log';'asin';'acos';'exp10';'square'])// Example taken from define_func2inv_d. Stores the list of some basic functions and their inverse// (for instance the inverse of function log is defined as function ... exp!)