using an app command in cas. (area)

[Angus]

hello,

recently there was some confusion about how to use and move data between different modes of the calculator. I, too, have still problems with that topic. I don't got trained on the prime at school nor do I use it on a daily basis, though. Maybe that is part of the problem.

What I was trying to to:

define a funtion inside the function app, say F1(X)=X^2-1.

switching to cas I can do something like F1' or diff(F1) which is what F1' is translated to. However say I need the area under the curve.
area(F1,0,1) gives 0 area(F1(x),0,1) gives 0 area(F1(X),0,1) gives 0.
AREA(F1,0,1) gives a result -0.66666(..)

There are some questions coming up from that. I understand that the area command has to be capitalized. How come that an "undefined" command area() gives a numerical result? e.g. foo(F1,0,1) does not behave like that - gives foo(X->(sq(X)-1),0,1). That makes sense to me since foo() cannot be resolved....

In the help screen it is said that AREA() "Finds the area under the function Fn or below Fn....." Where the Example is: AREA(-X,X^2,-2,1). My question is: As far as I think I understood functions and expressions I would call Fn and Fm an expression. Not a function. But AREA does also work with F1(X).

Maybe someone can explain the points and clear things up a bit more.

What do you people at HP think about data handling in general and the typing related issues (AREA is a pain to type in cas!). Do you see the problems many users have with understanding the interaction of parts inside the calculator and do you see some annoyance of different typings of variables, arguments and function names? Would you improve something if the managment let you?