HP-35’s x^y Why?
10-30-2021, 06:33 PM
Post: #1
 Matt Agajanian Senior Member Posts: 1,012 Joined: Dec 2013
HP-35’s x^y Why?
Hi all.

Yeah, all it takes is an x<>y press before the x^y key. So what was the reasoning for the 35’s x^y instead?

Thanks
10-30-2021, 06:43 PM
Post: #2
 toml_12953 Senior Member Posts: 2,079 Joined: Dec 2013
RE: HP-35’s x^y Why?
(10-30-2021 06:33 PM)Matt Agajanian Wrote:  Hi all.

Yeah, all it takes is an x<>y press before the x^y key. So what was the reasoning for the 35’s x^y instead?

Thanks

Reverse Polish Notation maybe?

To do 4^3

3
<enter>
4
x^y

Tom L
Cui bono?
10-30-2021, 07:41 PM
Post: #3
 TomC Senior Member Posts: 314 Joined: Dec 2013
RE: HP-35’s x^y Why?
Perhaps:

1. It was first on the history of handhelds. Later on the 45, perhaps HP felt that entering the base first was more 'natural'.
2. Perhaps it inherited it from the 9100 where the X Register Display was physically below the Y Register Display - thus the Y visually is above the X.

TomC

(10-30-2021 06:33 PM)Matt Agajanian Wrote:  Hi all.

Yeah, all it takes is an x<>y press before the x^y key. So what was the reasoning for the 35’s x^y instead?

Thanks
10-30-2021, 08:46 PM (This post was last modified: 10-30-2021 08:55 PM by Peet.)
Post: #4
 Peet Member Posts: 178 Joined: Oct 2020
RE: HP-35’s x^y Why?
I also suspect HP first chose the "logical" way with x^y (like x^2) but then noticed that y^x (like 10^x) feeled more natural to the user similar to simple arithmetic (like y enter x *).

Most curious is probably the Prime with an x^y key that does y^x

My calculators - former: CBM PR100, HP41CV, HP11C, HP28S - current: HP48G, HP35S, Prime, DM41X, DM42, HP12C
10-30-2021, 09:54 PM
Post: #5
 Gerson W. Barbosa Senior Member Posts: 1,560 Joined: Dec 2013
RE: HP-35’s x^y Why?
(10-30-2021 08:46 PM)Peet Wrote:  Most curious is probably the Prime with an x^y key that does y^x

How’s that again? I was thinking of finally getting myself a Prime, but your remark has made me think twice.
10-30-2021, 11:43 PM (This post was last modified: 10-31-2021 01:37 AM by Steve Simpkin.)
Post: #6
 Steve Simpkin Senior Member Posts: 1,132 Joined: Dec 2013
RE: HP-35’s x^y Why?
(10-30-2021 09:54 PM)Gerson W. Barbosa Wrote:
(10-30-2021 08:46 PM)Peet Wrote:  Most curious is probably the Prime with an x^y key that does y^x

How’s that again? I was thinking of finally getting myself a Prime, but your remark has made me think twice.

Well the Prime is, first and foremost, an *algebraic* graphing calculator. X^Y is not an unusual label for the power key on traditional algebraic calculators. It functions as a Y^X key in RPN mode.
Most modern algebraic models use the ^ key for powers now.

**Edited to fix the typo "Y^Y", It is now corrected to "Y^X".
10-31-2021, 12:00 AM
Post: #7
 lrdheat Senior Member Posts: 854 Joined: Feb 2014
RE: HP-35’s x^y Why?
I believe you mean that the key functions as an “x”^”y” key in RPN entry mode choice. In algebraic mode, in the text book mode, it is quite clear how the key works as hitting “x”, then x^y produces a curser space top right of “x’ for the “y” power to be keyed in.
10-31-2021, 12:23 AM
Post: #8
 Steve Simpkin Senior Member Posts: 1,132 Joined: Dec 2013
RE: HP-35’s x^y Why?
(10-31-2021 12:00 AM)lrdheat Wrote:  I believe you mean that the key functions as an “x”^”y” key in RPN entry mode choice. In algebraic mode, in the text book mode, it is quite clear how the key works as hitting “x”, then x^y produces a curser space top right of “x’ for the “y” power to be keyed in.

I think I had it correct. When the Prime is in RPN mode, the key labeled “X^Y” appears to function as a Y^X key just like the traditional HP RPN and RPL models (other than the HP-35). For example: 5 Enter 2 X^Y produces 25 as would be expected by RPN/RPL users.
10-31-2021, 01:09 AM
Post: #9
 rprosperi Super Moderator Posts: 6,192 Joined: Dec 2013
RE: HP-35’s x^y Why?
(10-31-2021 12:23 AM)Steve Simpkin Wrote:
(10-31-2021 12:00 AM)lrdheat Wrote:  I believe you mean that the key functions as an “x”^”y” key in RPN entry mode choice. In algebraic mode, in the text book mode, it is quite clear how the key works as hitting “x”, then x^y produces a curser space top right of “x’ for the “y” power to be keyed in.

I think I had it correct. When the Prime is in RPN mode, the key labeled “X^Y” appears to function as a Y^X key just like the traditional HP RPN and RPL models (other than the HP-35). For example: 5 Enter 2 X^Y produces 25 as would be expected by RPN/RPL users.

FYI - I think you're right, but in fact you did write it wrong just above where it says " It functions as a Y^Y key in RPN mode."

--Bob Prosperi
10-31-2021, 01:34 AM
Post: #10
 Steve Simpkin Senior Member Posts: 1,132 Joined: Dec 2013
RE: HP-35’s x^y Why?
(10-31-2021 01:09 AM)rprosperi Wrote:
(10-31-2021 12:23 AM)Steve Simpkin Wrote:  I think I had it correct. When the Prime is in RPN mode, the key labeled “X^Y” appears to function as a Y^X key just like the traditional HP RPN and RPL models (other than the HP-35). For example: 5 Enter 2 X^Y produces 25 as would be expected by RPN/RPL users.

FYI - I think you're right, but in fact you did write it wrong just above where it says " It functions as a Y^Y key in RPN mode."

Oops. I completely missed what lrdheat was trying to tell me. Sorry about that. I will edit my post to fix that typo. Thanks to both of you for spotting that.
10-31-2021, 07:45 AM (This post was last modified: 10-31-2021 11:47 AM by Peet.)
Post: #11
 Peet Member Posts: 178 Joined: Oct 2020
RE: HP-35’s x^y Why?
(10-30-2021 11:43 PM)Steve Simpkin Wrote:  Well the Prime is, first and foremost, an *algebraic* graphing calculator. X^Y is not an unusual label for the power key on traditional algebraic calculators.

e.g. TI59, TI30, HP22S or HP17B also had y^x because even on this algebraic calculators you type the base first and than the exponent. The HP35 way (exponent enter base -> x^y) was strange but the 35 was the first of its kind and HP didn't know any better at the time. The label on the Prime and a key what makes the opposite (Numworks shares this incoherent behavior) is very weird.

My calculators - former: CBM PR100, HP41CV, HP11C, HP28S - current: HP48G, HP35S, Prime, DM41X, DM42, HP12C
10-31-2021, 01:31 PM
Post: #12
 Dave Britten Senior Member Posts: 2,294 Joined: Dec 2013
RE: HP-35’s x^y Why?
As weird as x^y seems, it does make it easier to compute "power towers", e.g. 1.02^1.03^1.04^1.05^1.06 or similar. You actually start at the right side, so 1.05^1.06 first. 1.06 ENTER 1.05 x^y 1.04 x^y 1.03 x^y 1.02 x^y.
10-31-2021, 07:07 PM
Post: #13
 Steve Simpkin Senior Member Posts: 1,132 Joined: Dec 2013
RE: HP-35’s x^y Why?
(10-31-2021 07:45 AM)Peet Wrote:
(10-30-2021 11:43 PM)Steve Simpkin Wrote:  Well the Prime is, first and foremost, an *algebraic* graphing calculator. X^Y is not an unusual label for the power key on traditional algebraic calculators.

e.g. TI59, TI30, HP22S or HP17B also had y^x because even on this algebraic calculators you type the base first and than the exponent. The HP35 way (exponent enter base -> x^y) was strange but the 35 was the first of its kind and HP didn't know any better at the time. The label on the Prime and a key what makes the opposite (Numworks shares this incoherent behavior) is very weird.

Yes, I spoke too soon. While many early Casio scientific calculator models had X^Y keys, almost every other manufacturer had Y^X keys. No mater how they were labeled, they always worked the same way on algebraic models.
10-31-2021, 08:18 PM
Post: #14
 rprosperi Super Moderator Posts: 6,192 Joined: Dec 2013
RE: HP-35’s x^y Why?
Interesting, I don't think I've ever seen the predefined function X^(1/Y) before, never-mind have it right on the keyboard. Thx for sharing the photo.

--Bob Prosperi
10-31-2021, 08:26 PM
Post: #15
 Maximilian Hohmann Senior Member Posts: 1,250 Joined: Dec 2013
RE: HP-35’s x^y Why?
Hello!

(10-31-2021 07:45 AM)Peet Wrote:  e.g. TI59, TI30, HP22S or HP17B also had y^x

Even the Compucorps have it that way - only that it is labelled a^x. I always wondered why? Does anybody have an idea?

Regards
Max
10-31-2021, 09:18 PM
Post: #16
 Peet Member Posts: 178 Joined: Oct 2020
RE: HP-35’s x^y Why?
(10-31-2021 07:07 PM)Steve Simpkin Wrote:  No mater how they were labeled, they always worked the same way on algebraic models.

Algebraic calculator in the 70s and 80s were already illogical but I wouldn't expect that from a modern calculator like the Prime. It's better if the keys are labeled properly and not confused.

My calculators - former: CBM PR100, HP41CV, HP11C, HP28S - current: HP48G, HP35S, Prime, DM41X, DM42, HP12C
10-31-2021, 09:39 PM (This post was last modified: 10-31-2021 10:20 PM by Steve Simpkin.)
Post: #17
 Steve Simpkin Senior Member Posts: 1,132 Joined: Dec 2013
RE: HP-35’s x^y Why?
(10-31-2021 08:18 PM)rprosperi Wrote:  Interesting, I don't think I've ever seen the predefined function X^(1/Y) before, never-mind have it right on the keyboard. Thx for sharing the photo.

No problem, Bob Here are some other Casio models that had that key as well.
10-31-2021, 09:49 PM
Post: #18
 Didier Lachieze Senior Member Posts: 1,623 Joined: Dec 2013
RE: HP-35’s x^y Why?
(10-31-2021 08:26 PM)Maximilian Hohmann Wrote:  Even the Compucorps have it that way - only that it is labelled a^x. I always wondered why? Does anybody have an idea?

Canon scientific calculators also had a^x , from the F7 up to the F73 at least, but I don’t know why.
10-31-2021, 11:59 PM
Post: #19
 rprosperi Super Moderator Posts: 6,192 Joined: Dec 2013
RE: HP-35’s x^y Why?
(10-31-2021 09:39 PM)Steve Simpkin Wrote:
(10-31-2021 08:18 PM)rprosperi Wrote:  Interesting, I don't think I've ever seen the predefined function X^(1/Y) before, never-mind have it right on the keyboard. Thx for sharing the photo.

No problem, Bob Here are some other Casio models that had that key as well.

So, it seems to be a Casio-unique thing I guess? While the math of the operation is obviously of use for a variety of things, it seems an odd choice to allocate and commit to a permanently assigned key.

Didn't seem to catch on though... Odd.

--Bob Prosperi
11-01-2021, 12:51 AM
Post: #20
 Steve Simpkin Senior Member Posts: 1,132 Joined: Dec 2013
RE: HP-35’s x^y Why?
(10-31-2021 11:59 PM)rprosperi Wrote:
(10-31-2021 09:39 PM)Steve Simpkin Wrote:  No problem, Bob Here are some other Casio models that had that key as well.

So, it seems to be a Casio-unique thing I guess? While the math of the operation is obviously of use for a variety of things, it seems an odd choice to allocate and commit to a permanently assigned key.

Didn't seem to catch on though... Odd.

Very odd. I just noticed Casio is still including this function along with X^Y on at least one of their current models…
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