Each of this five items has the same submenu as Change. Selecting
one of the functions plots it (or its 1st or 2nd differentiation).
Numerical differentiations are calculated using the secant method.
Symbolic differentiations are calculated first and then the new
function is plotted (e.g. for sin(x): first cos(x) is calculated as
the differentiation of sin(x) and then it is plotted).
Symbolic differentiations are more precise but there are problems
with some function (abs, sgn, ln). E.g. for ln you get the function
1/x plotted even for negativ x.
When an error was found during plotting (division by zero for
example) a requester appears with the message "There was an error".
To stop plotting, click in the window. A requester appears and you
can select whether to continue or stop.