Hi,
Actually, the 33s has three different data entry/interface paradigms:
1. RPN
2. Equation List > Algebraic Expression parser
3. ALG > old style "Algebraic" operation interpreter
Note that the RPN and ALG modes are direct calculation interfacesnot expression parsersyou have the "equation list" for the latter. (It is very unfortunate that the equation feature does not have provision for editing!)
All old style HP, Casio, Sharp, Ti etc etc (including a number of current $15 Casios) "algebraics" work with infix for the basic operations +x/, and postfix for all "one number" functions. So, I do not think it is right to see this feature as a flawit allows one to be efficicent with keystrokesand to use results for the next computation without having to resort to jumping through hoops, like SIN (2nd ANS) ENTER to get the sin of the last result (this is what you do on a 30s for example).
I think it would have been impossible for the existing RPNbased keystroke programming code to have worked with both RPN and a "direct algebraic logic" type of interfaceor it would have been much more difficult at any rate. I would say that it might be worth exploring, though. The way Alg has been implememented on the 33s is fundamentally the same as the 20s and 21s.
Perhaps it is confusing to have the fancy two line diplay show the sin(x) when you have typed x sin.
I think the 33s has bigger problemsthe bugsthan whether the ALG interface is perfect.
The real problem with the ALG interface is that there is no good documentationI have had to discover how LastX, X<>Y etc work, on my own. (And in fact you will see that there are two different implementations of the X<>Ythe newer versions actaully use X<>Y to create a second parallel ALG stackyou can work on two ALG computations at the same time, and tie them together. In fact, you can also use this feature in a program, as a way to implememt a counter or test variable, without having to use any of the letternamed variables:
LBL A
X<>Y
CODE
CODE
etc
X<>Y

1
X>0?
GTO A
RTN
or the like....
REgards,
Bill
Edited: 5 Aug 2004, 12:50 p.m.