HP calcs with X^Y function


Most of calcs have Y^X function.
How many calcs can you find with X^Y function?


As far as I know, only :
- HP 9810A
- HP 35

have the x^y function. Is that right ?


I think there are more...


Yes, there are more. The HP-38G is one of them. The HP-39G is another. There may be more.

What's funny is that neither has an X- or Y-register per se (as far as I know), so the label is meaningless anyway.



Some of the newest algebraic calcs have X^Y function. Others have Y^X. Both seems to act in the same way. So why the labels are different?

Compare HP 39G/40G, HP 30S, HP 6S


I mean that the calcs I mentioned really calculate x^y accoding to the position of the numbers in the stack; this is not the case for the later models you mentioned...

However keep on posting some more quizzes, I really enjoy it



This is something I did not notice so far. Yes, I agree with Thibaut: the HP35 was the first - and the only - pocket RPN with x^y. All others offered [y^x] function (and label) to agree with other non-commutative math operations, i.e.: /, -, %. (Please, if the term commutative is not used this way, forgive-me and help me placing the correct one.) Say, 4-7 is not equal to 7-4, while 4+7 is equal to 7+4 (mathematical results). Raising to a power is non-commutative. Let's take this: at the moment we need 4-3, the sequence 4 ENTER 3 [-] will give the expected result; what about 4^3? We would place 4 ENTER 3 [y^x]; if there is a [x^y] function, the sequence should be 3 ENTER 4 [x^y] (remember, x and y reffer to stack-registers X and Y).

The algebraics differ for the math sequence: 4 [x^y] 3 [=] works fine, as 4 [y^x] 3 [=] is confusing for those already familiar with algebraic notation.

With RPN models, the input sequence will really dictate who will be raised to who, but [y^x] will always mean [y-contents ^ x-contents]. In the new ones, y- meaning level 2 argument, and x- meaning level 1 argument. With the 49G, the [y^x} key adds a single [^] character, algebraic or RPN mode.



If I recall correctly, the HP35 does not have an "antilog" key, so the reason to have x^y instead of y^x is to make it easy to do 10 x^y as an antilog shortcut.

Possibly Related Threads...
Thread Author Replies Views Last Post
  HP50g: Writing a function that returns a function Chris de Castro 2 1,015 12-10-2013, 06:49 PM
Last Post: Han
  IFERR function on HP Prime Mic 2 880 12-02-2013, 01:33 AM
Last Post: cyrille de Brébisson
  [Download] libhpcalcs: a toolkit for communicating with Prime calcs... debrouxl 13 2,051 11-18-2013, 05:22 AM
Last Post: debrouxl
  HP Prime: Dirichlet's eta function recognized but not numerically evaluated Helge Gabert 0 572 11-16-2013, 03:41 PM
Last Post: Helge Gabert
  Possible bug with sqrt function in the HP prime Michael de Estrada 6 1,107 11-15-2013, 12:49 PM
Last Post: Michael de Estrada
  HP-41 MCODE: The Last Function - at last! Ángel Martin 0 527 11-08-2013, 05:11 AM
Last Post: Ángel Martin
  HP Prime 'where' function bluesun08 11 1,708 10-29-2013, 06:56 PM
Last Post: Joe Horn
  Swiss Micros calcs Mike Powell 6 1,232 10-26-2013, 05:03 PM
Last Post: Mike Powell
  HP Prime - Defining a function bluesun08 5 1,059 10-23-2013, 02:43 PM
Last Post: Han
  HP PRIME Function parameters steindid 2 707 10-11-2013, 10:20 AM
Last Post: steindid

Forum Jump: