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Hard to believe but does HP not make RPN scientific calculators anymore? I have a 15C, bought in 1984, and a 48G, bought in 2000. I'd love to get my hands on a 42S or 32SII, or equivalent, but they're priced so exorbitantly on sites like Ebay, etc.
I wonder if HP realized what they're missing by ending production of RPN scientific calculators.
Comments??
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It may be that the HP12C/CP is the only pure RPN line left.
But HP is going to make several new models which are optionally (userselectable) RPN or AOS.
See The Samson Cables Catalog for more info . . .
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I like RPN just as well as others but I don't understand the big deal with RPN vs Algebraic. Neither is really any better (really) than the other. It's simply personal preference.
Being that, the world is comprised of mostly algebraic people. From a business sense, it makes sense to drop the RPN. It is a much smaller market and really offers nothing that can't be done by the algebraic calculators.
It's like FORTH. Many like it but it's a tiny part of the computer segment.
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I think algebraic mode makes great sense for music majors and Fortran programmers  they are well used to the extra punctuation necessary.
My dad also mentioned that there were bunches of guys at Cornell in the 50's that got along well with those cheapie printed metal slide rules instead of decent Versalogs and Decilons, etc.
I guess it's a matter of taste after all.
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Quote: I like RPN just as well as others but I don't understand the big deal with RPN vs Algebraic. Neither is really any better (really) than the other. It's simply personal preference.
Fewer keystrokes for a given problem. Wasn't that _one_ of the reasons HP decided to use RPN?
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While that is Hp's advertised reason, the real reason was functions and features vs. adding AOS and giving up functions. The earlier machines (ie Hp35) had very limited memory to add features. RPN made the user keep track of operations, which made for fewer keystrokes as a bonus. This bonus of fewer keystrokes sounds better than, "We don't make algebraics because we can't offer Algebraic input and trig in the same pocket calculator (this applied to the Hp35)." That the Hp35 was so popular and RPN was so good kept RPN as the preferred OS for Hp calcs for the next two decades.
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In addition to numerous HP calculators, I also have a few other brands. Whenever I buy another type of calculator I always use the following equation, from page 106 of the HP67 Owner's Handbook, to test the useability of the new calculator. Using an HP calculator usually takes about 45 seconds to get the correct answer. Using an algebraic calculator usually takes much longer, twenty minutes or more, if it in fact can solve the problem at all. This equation calculates the Mach number given pressure altitude and calibrated air speed. All the variables have been substituted into the equation, you need only calculate the answer.
M= sq. root of [ 5 [({[( 1 + 0.2 [ 350/661.5 ]^2 )^3.5 1 ]
[ 1 ( 6.875^106 ) 25500 ]^5.2656 } +1 )^0.286 1 ] ]
Even trying to enter this equation into an HP48GX or 49G+ equation writer is a difficult task.
If you really want to see how much easier RPN is, try to calculate the answer to this problem using an algebraic calculator. Post your answer and an honest estimation of how long it took you and I will then post the correct answer as given in the 67 handbook. I think you will agree the HP is easier.
rdb.
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I used the HP48G strictly with RPN entry and I got 8.35049933621x10^13 as the answer, though in about 2 and a half minutes, glancing at the 48G's clock display in the upper right hand corner.
As a note, I first tried my HP32SII and it didn't work, as I got an "Invalid y^x error". Then I went to my favorite, though somewhat intermittent HP34C, and got an "Error 0". I broke down and reached for the 48G.
After looking at R. D. Baertschiger's convoluted Mach equation, I WASN'T going to even try with the algebraic HP20S (and definitely not with the Radio Shack algebraic scientific (cat. no. 651081) (double for the Sentry scientific).
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Sorry you thought the equation was convoluted. I tried to copy it as shown in the 67 handbook. The two lines should of course be all on one line. The square root is taken of the entire rest of the equation. As I said, just entering it into the message was a chore. As to your answer... Sorry, wrong answer. Please try again.
rdb.
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Mr. Baertschiger, this time I got 0.835724535179 (to include all the digits) again using the HP48G, but it took one minute and a half, using Mr. Hardman's display of the equation.
Please allow me to point out that on your posting, you specified 6.875^106, which I did not understand properly (and I apologize!) when I expected 6.875x10^(6).
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Yes! You are correct. I just realized this mistake myself a few minutes ago. I was about to post a correction. I guess it is a little late now for that. I think you will agree however, that rpn is much easier than any other method.
rdb.
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Hee hee hee... you are preaching to the converted! After my first taste of RPN, I was hooked. It was the 34C, by the way.
And since now I have the correct Mach equation, I'll try it again on the 34C (if I can get all the LEDs to light up) and on the 32SII. If you are interested, I'll let you know how I did.
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Is the answer 6.9541e1? I used my 32sii. I love rpn, but after 7.5 hrs of hw, and a bruski, well..you know.
el
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No.
Check one of Mark Hardman's posts in the thread; he has a corrected version of the way the equation is laid out. I strongly suspect you may have calculated using an incorrect version of it.
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I just reread your answer, remember we are looking for a mach number for an airplane in flight. Therefore the answer will be between ca. .25 & 1.
I have entered this equation into a word document where it looks as it should. However I have not been able to figure out how to paste the equation by itself into a message here on the museum.
rdb.
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How is this?
Edited: 3 Oct 2003, 9:16 p.m.
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Yes. That is the equation exactly. May I be so bold as to inquire how you entered it here? Thank you.
rdb.
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Nothing magical. I cut the image straight out of the HP67 manual on the MoHPC DVD, saved it as a .gif and uploaded it to my web site.
By the way, I was able to crank through this in 10'13" using the low end HP20S. I ran out of paren () levels well before the innermost 350/661.5 term. I had to start over and use a storage register.
The answer is 0.8357.
It took me 2'43" to get the same result on a HP41CX.
Mark Hardman
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Mr. Hardman:
Your answer is correct, however I was hoping Mike would respond.
rdb.
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Whoo! Ok, I got it on my third try. 8.3472e1 on my favorite machine as of now, the orange/blue printed 32sii! This is a great way to unwind after a stressy day! I'd love to see the ti kids fiddling with this one....'hang on my 89 says I'm missing a parenthesis...uh..hmmm..lemme start over....hey what'd you get?' Great fun. No hard feelings tisypathetics, I got through my first physics course with an 86.
el
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I got the correct answer at first attempt on my 15c and on my 48GX, but I needed three attempts on my algebraic Casio fx4000p :P I love RPN
Raul
Edited: 4 Oct 2003, 10:55 a.m.
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The correct answer is: 0.835724535179
given in the 67 handbook as 0.84
The proper key stroke sequence is:
350 ENTER
661.5 /
X^2
.2 *
1 +
3.5 Y^X
1 
1 ENTER
6.875 EEX CHS 6
ENTER
25500 *

5.2656 CHS Y^X
*
1 +
.286 Y^X
1 
5 *
SQ. ROOT
rdb.
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The same equation keyed into a 71b...
SQR(5*((((1+.2*(350/661.5)^2)^3.51)*(1(6.875E6)*25500)^(5.2656)+1)^.2861))
I'm a fan of RPN also.
Terry
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Can a 48gx user please post a stepbystep procedure for solving the Mach problem posted by Mark Hardman, usign the equation writer of the 48gx?
I have a 48gx, but have only learned how to use the basic rpn operations. This would be a big help to see sidebyside examples/procedures.
If the equation writer is not the best way to solve this, are there another way, besides using the rpn keystrokes as listed in a previous post?
Thanks,
Terry
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The easiest way is is to use the rpn keystrokes as I listed them earlier. I have also tried to enter this equation into the equation writer of both a 48gx and a 49g+. It can be done, but is much more difficult because you can not see all of the equation at one time as it takes up more and more of the screen. Also making corrections is not very straight forward.
I will try to to make a list of the necessary keystrokes to enter it into the equation writer and post the list later.
rdb.
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Here are the keystroke sequences for entering the equation into an HP48GX or HP49G+ calculator:
Procedure for HP48gx:
left shift equation
square root
5
left shift parenthesis
left shift parenthesis
left shift parenthesis
left shift parenthesis
left shift parenthesis
1 + 0.2
left shift parenthesis
350 / 661.5
right arrow
right arrow
y^x
2
right arrow
right arrow
y^x
3.5
right arrow
 1
right arrow
left shift parenthesis
1 
left shift parenthesis
6.875 * 10 y^x chs 6
right arrow
right arrow
25500
right arrow
y^x
chs 5.2656
right arrow
right arrow
+ 1
right arrow
y^x 0.286
right arrow
 1
right arrow
enter
You should now store the equation:
'machno' STO
If the equation was entered correctly, then pressing
'machno'
then 'eval' should return 0.84.
If not then check the equation as entered and edit it as necessary.
Procedure for HP49G+, must be set to 'rpn' mode:
right shift eqw
square root
5
left shift parenthesis
left shift parenthesis
left shift parenthesis
left shift parenthesis
left shift parenthesis
1 + 0.2
left shift parenthesis
350 / 661.5
right arrow
right arrow
y^x
2
right arrow
right arrow
right arrow
right arrow
y^x
3.5
right arrow
 1
right arrow
right arrow
right arrow
*
left shift parenthesis
1 
left shift parenthesis
6.875 * 10 y^x chs 6
right arrow
right arrow
right arrow
right arrow
*
25500
right arrow
right arrow
right arrow
right arrow
y^x
chs 5.2656
right arrow
right arrow
right arrow
right arrow
+ 1
right arrow
right arrow
y^x 0.286
right arrow
 1
enter
You should now store the equation:
'machno' STO
If the equation was entered correctly, then pressing
'machno'
then 'eval' should return 0.84.
If not then check the equation as entered and edit it as necessary.
rdb.
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Thanks for this example. I'll give it a try...
Looks quite a bit more complicated than RPN. In fact, almost everything that I try to accomplish with the 48gx takes longer and is more difficult than the more simple RPN keystroke models.
I'm not trying to bash the 48gx, but only admitting that I don't fully understand how to operate the machine, but still want to continue trying to learn.
Your equation editor procedure will certainly help.
Can the 48gx also use parenthesis to solve the Mach formula without using the equation editor, similar to the 71b listing previously posted?
I use RPN (41cv, 32Sii)for a lot of calculations, but still find the 71b style of entry easy for some formulas also.
Thanks again for your time,
Terry
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Can the 48gx also use parenthesis to solve the Mach formula without using the equation editor, similar to the 71b listing previously posted?
Yes. However you need to add a few more pairs of parenthesis at certain places, there are already enough of these, and then if you need to edit the equation, it will be loaded into the equation writer anyway. Why not just stick with 'rpn'? Much easier.
rdb.
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Interesting test. When I tried it, two strange things happened :
1) I typed the equation in under 30 seconds on the algebraic machine that was available at the time (shame prevents me from saying what it was, but it's under the $50 tag)
2) The result displayed is 0.8279147828
Can this test be THAT simple and the result be THAT inaccurate ??
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With the MetaKernel, the equation writer is diferent and faster (very very faster)
Sq root
5
*
1
up
+
.2
*
350
up
/
661.5
right
yx (this means "raised")
2
right
right
right
yx
3.5
right

1
right
*
1
up

6.875
EEX
6 +/
*
25500
right
right
yx
5.2656 +/
right
right
+
1
right
yx
.286
right

1
enter
EVALuating this, you must get 0.835724535179
Edited: 4 Oct 2003, 6:08 p.m.
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Hard to say why your answer is different. Perhaps you entered a number wrong or a function. The point is; Now that you see that a wrong answer could happen are you really ready to trust algebraic input? I am not, therefore I will continue to use rpn.
rdb.
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You miskeyed the 25,500 term. I get the same (wrong) answer if I use 25,000. This mistake likely was caused by your need to concentrate on the level of parens in use and not on the values being entered.
<grin>
Mark Hardman
Edited: 4 Oct 2003, 7:16 p.m.
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There's no argument here. I like RPN too.
I still like to use the 71b and probably would vote the 71b as my "must have" calculation device. I just wish the machine had RPN style entry. I sometimes use the RPNLEX file created by JR Baker with the 71b. This is really a great lex file, but the program is missing storage register ability.
Thanks again for the procedure listings,
Terry,
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A much easier way to get it into the Equation writer is to simply type in:
'Sqrt(5*(((((1+.2*(350/661.5)^2)^3.51)*(16.875E6*25500)^5.2656)+1)^.2861))'
(type the square root symbol on the keyboard instead of Sqrt)
Then press the down arrow on the keyboard to begin editing in the Equation writer.
You will see the expression in all its glory. Scroll back and forth with the left and right arrow keys.
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Quote: given in the 67 handbook as 0.84
I think, this is the correct answer. I don't know what's that formula (but I'll an mechanical engineer  specialised for fluid's mechanics).
That's seems to me like a empirical formula. And all of terms have got 45 significant digits. If we use this calculations, the result's significant digits no more than 2 or 3.
And what's this M really ;) ? (M=0.84 is enough, I think...)
Csaba
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Arun posted:
"I wonder if HP realized what they're missing by ending production of RPN scientific calculators."
First, there's no "ending" at all, HP's releasing new scientific calculators with RPN and/or RPL modes right now.
Second, HP would miss *nothing* if they stopped dead production of RPN/RPL calculators altogether. Only a bunch of diehards like us care at all about RPN, the 99.999% of people using a calculator couldn't care less about it, and it's not clear at all that they're "missing" anything and need to be "saved" from their error in not realizing just how superior RPN is, because to begin with, it actually isn't. The mere fact that you or me like it does not make it "superior" in the least.
That being so, HP is not a charity but a profitdriven organization, and if RPN calcs aren't economically profitable, which frankly they aren't, they're doing the right thing dropping them out of production. If it were your enterprise and your money, you'd do the same.
Anyway, you'll be able to sharpen your teeth with the new Kinpo ... erm, I mean HP, models. They'll calm your addiction for a while but think twice before introducing any children of yours to the joys of RPN: it's a crippling, blinding addiction for sure. Or would you prefer to be in the losing side of the Beta vs. VHS rage ? :)
Best regards from V.
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I think valentin's post makes the most sense of anything I've read in the Forum today.
LC
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Quote: I think valentin's post makes the most sense of anything I've read in the Forum today.
It makes sense if you think of HP as just another moneygrubbing company trying to make a few bucks. I used to think HP was better than that...
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Valentin Albillo said, in response to No RPN calcs. anymore??, posted by Arun
They'll calm your addiction for a while but think twice before introducing any children of yours to the joys of RPN: it's a crippling, blinding addiction for sure. Or would you prefer to be in the losing side of the Beta vs. VHS rage ? :)
******
Go ahead and introduce your kids to the joys of RPN.
With computers decreasing in size and increasing in power and portibility, there will always be plenty of "software" RPN for the beautiful minds, even if HP does manage to kill the hardware version. RPN WILL LIVE ON!
It's too late for Beta though, Sorry.
Euclid
www.livingsoftware.net
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Well, I'd rather be an RPN user forced to convert back to algebraic, that poses no difficulty. The only problem is being a little slower for a while. Now, learning rpn, and I mean REALLY learning rpn, is something that takes some effort.
I used to be a power house algebraic ti86er, yeah I could evaluate expressions quickly, but after returning to the rpn platform, I appreciate the thought process that is involved with rpn. Consider this, using rpn takes some thought, algebraic does not really. I get some satisfaction from knowing that thought goes into my calculations, and that I'm not just a dataenterer. I understand that there are people out there committed to algebraics, and that is ok with me. I think that you will become fluent in any form of entry you practice. Let's all just enjoy what we have and appreciate that we have choices, :)
el
