HP calcs with X^Y function « Next Oldest | Next Newest »

 ▼ mapet Member Posts: 57 Threads: 27 Joined: Jan 1970 01-17-2002, 02:59 AM Most of calcs have Y^X function. How many calcs can you find with X^Y function? ▼ Thibaut.be Senior Member Posts: 610 Threads: 53 Joined: Aug 2005 01-17-2002, 03:20 AM As far as I know, only : - HP 9810A - HP 35 have the x^y function. Is that right ? ▼ mapet Member Posts: 57 Threads: 27 Joined: Jan 1970 01-17-2002, 03:24 AM I think there are more... ▼ Ernie Malaga Senior Member Posts: 312 Threads: 25 Joined: Jan 1970 01-17-2002, 07:06 PM 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. -Ernie ▼ mapet Member Posts: 57 Threads: 27 Joined: Jan 1970 01-18-2002, 03:26 AM 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? PS Compare HP 39G/40G, HP 30S, HP 6S ▼ Thibaut.be Senior Member Posts: 610 Threads: 53 Joined: Aug 2005 01-18-2002, 04:47 PM 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 Vieira, Luiz C. (Brazil) Posting Freak Posts: 4,027 Threads: 172 Joined: Aug 2005 01-21-2002, 12:09 AM Hi; 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. Cheers. ▼ Andrés C. Rodríguez (Argentina) Posting Freak Posts: 1,193 Threads: 43 Joined: Jul 2005 01-23-2002, 04:59 PM 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.

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