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Full Version: HP calcs with X^Y function
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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.

-Ernie

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

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

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.

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.