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Advice to buy an HP
04-16-2015, 06:01 PM
Post: #21
RE: Advice to buy an HP
Quite right, jebem, HP have produced updates for the operating system.

Is there any evidence that the sum total of malfunctions & their severity has decreased?
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04-16-2015, 09:54 PM
Post: #22
RE: Advice to buy an HP
I've found the HP 50g blue model for 100€. I think it's quite expensive. Is there anything different apart from the color?.
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04-16-2015, 10:04 PM (This post was last modified: 04-16-2015 10:15 PM by bshoring.)
Post: #23
HP-80
(04-16-2015 01:57 PM)Don Shepherd Wrote:  
(04-16-2015 01:21 PM)TASP Wrote:  I realize the rest of the speed demons here will hate this, but the fluttering of the LED display while the 80 chugs and snorts it's way thru problems is fun. The age of the thing and it's date arithmetic functions are interesting too. The 'wonky' enter button that says 'SAVE ^' is another source of amusement with every press.

Also, just a luck of the draw thing, the one that wound up in my hands looks pristine, who ever had it before took the batteries out apparently a week after buying it and left it in his office drawer ever since.

The top row of keys, "n i PMT PV FV" is amazing too. I don't have much need of financial functions, but even I can appreciate just how bloody brilliant that row of keys is and how the software works. And how many subsequent calculators have those keys on them ?? Heck, even the PPCROM emulates that feature!

I think it's age, durability, good looks, and out of the gate advanced design just make it a really neat thing to have around and use. It feels good in my hand as has the right amount of 'heft'. Amazing, HP's second handheld calculator still stands as a primer for everyone else making calculators to this day.

Of my 3 oldies, the 35, 45, and 80, it was the only one that came with a charger, and it is keeping all 3 of them working too. Just another little bonus.

Wow, I never paid any attention to the HP-80 before, but I admire its simplicity and no-frills approach. Thanks for bringing this up.

Does your HP-80 also have the LED fluttering with the square root and x^y functions, while the HP-35 does not? An emulator I have for the HP-80 has the fluttering for those functions, as well as the financial functions. I think it's kind of fun. What impresses me is how HP managed to pack so many financial functions into such an early machine with limited ROM & RAM. Since it has no financial registers (even the HP-70 has them), it has to perform all the financial work using only the 4 registers of the stack, plus the two internal "scratch" registers, A & B. I believe for solving for i (interest rate) which must use Newton's Method, the single storage register is also used.

Fascinating machine.

Bob
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04-16-2015, 11:28 PM
Post: #24
RE: Advice to buy an HP
(04-16-2015 09:54 PM)Cancuino Wrote:  I've found the HP 50g blue model for 100€. I think it's quite expensive. Is there anything different apart from the color?.

I'vê never used a Blue one, but some fellow here do, and they say There's no difference apart color.

I paid at about 100 euro here in my country, but you know, there's always shpping cost and import taxes to pay.

I am certain you will be delighted with the 50g. Many here do, and so am I.

Cheers

JL
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04-16-2015, 11:39 PM
Post: #25
RE: Advice to buy an HP
Thanks Jlouis, I wasn't sure if there is any other different apart from the color because the blue one uses to be cheaper.
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04-16-2015, 11:47 PM
Post: #26
RE: Advice to buy an HP
(04-16-2015 08:01 AM)Cancuino Wrote:  I meant structural engineering. It's getting harder than I thought to take a choice Big Grin.

On reading your first post, my instinctive reaction was: get a 50G. It will build on what you have already learned about the 48G (and that's not a trivial amount) and give you more speed, more memory, more everything, really.

But if you have a little spare cash and time, you might enjoy picking up a 41CV or 41CX on an auction site, especially if you can find the Structural Analysis Pac for it. The Pac has programs for calculating properties of polygonal sections, various types of beams, etc. The manual is on the MoHPC "DVD" (really, a USB key these days).

But the 41 is an older, simpler calculator, and if you're already reliant on the 48G, then the 50G is almost a no-brainer.

--- Les
[http://www.lesbell.com.au]
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04-17-2015, 01:33 AM
Post: #27
RE: Advice to buy an HP
(04-16-2015 11:47 PM)Les Bell Wrote:  especially if you can find the Structural Analysis Pac for it.

Completely coincidentally, I just took a look at That Auction Site - you know, the one with a name that begins with "eB" and ends with "ay" - and there's a Structural Analysis Pac newly listed on it, complete with box, manual and keyboard overlays. You can probably pick up a 50G for about the same price as that Pac alone, though. (And no, I'm not the seller).

--- Les
[http://www.lesbell.com.au]
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04-17-2015, 01:56 AM
Post: #28
RE: Advice to buy an HP
I chose the 50g earlier this year and am very happy. After a few weeks of daily use the menu's don't bother me, but of course YMMV.

Before I purchased, I installed on my windows PC the free emulators for the Prime, 50g, and 34S and worked through a little of the manuals. As far as I can remember:

The prime emulator was from the HP company calculator site,

The 50g emulator is emu48+ from hpcalc.org, make sure you get the plus version.

The 34S emulator is found at http://wp34s.sourceforge.net/

Good Luck,

Mark
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04-17-2015, 02:13 AM (This post was last modified: 04-17-2015 02:19 AM by Marcio.)
Post: #29
RE: Advice to buy an HP
While most will recommend the 50g, I will go against the flow and recommend the Prime instead.

I suspect most bad things you have heard about the Prime are not quite fair or even accurate. Many wanted the Prime to be perfect in every detail, and it's not, but I guarantee it is WAY faster than any other HP calculator (if not the fastest available in the market), will offer you a very wide range of options, its programming is extremely easy to master and not to mention its graphing capabilities which is beyond anything you've seen in a calculator.

Search YouTube and the forums for more info and you will see what I'm talking about.
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04-17-2015, 08:41 AM
Post: #30
RE: Advice to buy an HP
(04-16-2015 06:01 PM)Gerald H Wrote:  Is there any evidence that the sum total of malfunctions & their severity has decreased?

Hi, Gerald.

That will be the HP best kept secret!

But from the release information notes (release_info.txt files) included in the official firmware releases, we see that the HP PRIME team has been kind of busy killing those nasty bugs, many of them found and reported here in the MoHPC.

Let's see:

Date Released: 2014/12/03
Firmware Version: 2014 12 03 (6975)
Virtual Calculator Version: 2014 12 03 (6975)
Connectivity Kit: 2014 12 03 (6975)

- General machine fixed bugs: 46
- Specific CAS environment fixed bugs: 73
- New calculator features: 12
- New virtual calculator features: 2
- New Connectivity Kit features: 7


Date Released: 2014/07/02
Firmware Version: 2014 07 02 (6031)
Virtual Calculator Version: 2014 03 31 (6031)
Connectivity Kit: 2014 03 31 (6026)

- General machine fixed bugs: 1


Date Released: 2014/03/31
Firmware Version: 2014 03 31 (6030)
Virtual Calculator Version: 2014 03 31 (6031)
Connectivity Kit: 2014 03 31 (6026)

- General machine fixed bugs: 40
- Specific CAS environment fixed bugs: 75
- New calculator features: 19
- New virtual calculator features: 1
- New Connectivity Kit features: 3


Date Released: 11/25/2013
Firmware Version: 2013 11 25 (5447)
Emulator Version: 2013 11 25 (5447)
Connectivity Kit: 2013 11 25 (5442)

- General and including CAS fixed bugs: 73


The official HP Prime software and documentation FTP repository location is:
Code:

ftp://ftp.hp.com/pub/calculators/Prime/


Attached File(s)
.txt  release_info.txt (Size: 31.75 KB / Downloads: 3)

Jose Mesquita
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04-17-2015, 09:42 AM
Post: #31
RE: Advice to buy an HP
I have many HP calculators including the HP Prime & at this stage I recommend, like many, the HP 50G. It is an absolute bargain when you consider its capabilities & it is the calculator I choose to use every day as a practicing engineer.

Cheers,

Michael
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04-17-2015, 02:00 PM
Post: #32
RE: Advice to buy an HP
Thank you all for your answers. I've come to a conclusion and bought the 50g, I think that overall it's the best choice for me.

I'll keep reading you to learn how to use it really well.
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04-17-2015, 05:09 PM
Post: #33
RE: Advice to buy an HP
(04-16-2015 10:04 PM)bshoring Wrote:  
(04-16-2015 01:57 PM)Don Shepherd Wrote:  Wow, I never paid any attention to the HP-80 before, but I admire its simplicity and no-frills approach. Thanks for bringing this up.

Does your HP-80 also have the LED fluttering with the square root and x^y functions, while the HP-35 does not? An emulator I have for the HP-80 has the fluttering for those functions, as well as the financial functions. I think it's kind of fun.

. . . . . . ..

You're correct, the HP35 doesn't 'flutter' and the HP80 does. And one has x^y, and the other is y^x (don't make me go look as to which is which)


My HP25, as I recall, fluttered too.


Fun watching them thrash their way thru the code, ain't it ?

Wink

2speed HP41CX,int2XMEM+ZEN, HPIL+DEVEL, HPIL+X/IO, I/R, 82143, 82163, 82162 -25,35,45,55,65,67,70,80
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04-18-2015, 02:19 PM
Post: #34
RE: Advice to buy an HP
(04-16-2015 10:04 PM)bshoring Wrote:  I believe for solving for i (interest rate) which must use Newton's Method, the single storage register is also used.

The algorithm used to calculate i when n, PMT and PV are given can be found in APPENDIX A of A Pocket-Sized Answer Machine for Business and Finance.

Quote:For a variety of reasons the best technique to try is the Newton-Raphson one and this was used for the annuity functions.

There's also flow chart in Fig. 3 but the initial value i0 has a typo: the number 2 should be in the numerator:
\[i_0 = \frac{2(n-P)}{n(n+1)}\]

A similar flow-chart can be found in Fig. 32 of United States Patent 3863060 on page 25 where it is correct.

I was wondering how they arrived at that initial guess:
Quote:First we sum the first three terms of the binomial expansion for f(i) and solve for i.

It turns out they just used the Taylor series as can be seen using Wolfram|Alpha:

Series[P-(1-(1 + r)^(-n))/r, {r, 0, 1}]

\((P-n)+\frac{1}{2}n(n+1)r+O(r^2)\)

Solve[(P-n)+1/2 n (n+1) r, r]

\(r=\frac{2n-2P}{n^2+n}\) and \(n(n+1)\neq0\)

Cheers
Thomas
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04-19-2015, 04:38 AM
Post: #35
RE: HP-80
(04-18-2015 02:19 PM)Thomas Klemm Wrote:  
(04-16-2015 10:04 PM)bshoring Wrote:  I believe for solving for i (interest rate) which must use Newton's Method, the single storage register is also used.

The algorithm used to calculate i when n, PMT and PV are given can be found in APPENDIX A of A Pocket-Sized Answer Machine for Business and Finance.

Quote:For a variety of reasons the best technique to try is the Newton-Raphson one and this was used for the annuity functions.

There's also flow chart in Fig. 3 but the initial value i0 has a typo: the number 2 should be in the numerator:
\[i_0 = \frac{2(n-P)}{n(n+1)}\]

A similar flow-chart can be found in Fig. 32 of United States Patent 3863060 on page 25 where it is correct.

I was wondering how they arrived at that initial guess:
Quote:First we sum the first three terms of the binomial expansion for f(i) and solve for i.

It turns out they just used the Taylor series as can be seen using Wolfram|Alpha:

Series[P-(1-(1 + r)^(-n))/r, {r, 0, 1}]

\((P-n)+\frac{1}{2}n(n+1)r+O(r^2)\)

Solve[(P-n)+1/2 n (n+1) r, r]

\(r=\frac{2n-2P}{n^2+n}\) and \(n(n+1)\neq0\)

Cheers
Thomas

Thanks, Thomas. You provided a lot of good information and the two links you referenced are worth reading for anyone interested in the HP-80 or any of the financial calculators that followed. Also, in case anyone missed it, there is a great article by Max Stone at:
http://www.hpmuseum.org/cgi-sys/cgiwrap/...?read=1263
with a lot of good stuff.

The HP-80 really did set the standard for all the financial calculators. The basic operation is pretty much incorporated in the legendary HP-12C, though with many improvements. I am still amazed at how much functionality HP managed to pack into this instrument back in 1973, with such limited ROM and RAM, and no independent financial registers.

Even though the machine has no keys for logarithms & anti-logs, there are some clever ways to get both common and natural logs using the financial keys, outlined in "Application Notes" entitled "Calculating Logs, anti-logs and roots of numbers." If anyone's interested, I can give specifics.

Also the Trend Line function is actually quite effective, if X-Values are evenly spaced, as you can only input the Y values, as the X-Values are implied as 1,2,3,etc. But once you do the compute function, you can predict a Y value for any X value, including fractional values. So there is more there than meets the eye.

Really a great, and well thought out machine !

Bob
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04-19-2015, 05:18 AM (This post was last modified: 04-19-2015 11:33 PM by Thomas Klemm.)
Post: #36
RE: HP-80
(04-19-2015 04:38 AM)bshoring Wrote:  Even though the machine has no keys for logarithms & anti-logs, there are some clever ways to get both common and natural logs using the financial keys, outlined in "Application Notes" entitled "Calculating Logs, anti-logs and roots of numbers." If anyone's interested, I can give specifics.

Yes, please do so.

Thanks in advance
Thomas
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04-19-2015, 09:11 PM
Post: #37
RE: Advice to buy an HP
Although I've already bought the HP, I've just read about the TI 89 titanium, is it that good?. I've never tried a TI and want to be sure that the HP is the best choice.

Thanks.
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04-19-2015, 09:15 PM
Post: #38
RE: HP-80
Thomas and others,
Regarding Logs and Anti-Logs on the HP-80

To get a common logarithm or natural logarithm, use the following keystrokes:

900 i , 1 PV, (number) FV (where "number" is the value you want the logarithm for). Then pressing "n" leaves the common log in X-Register and natural log (Ln) in Y-register.

So, for the LOG and Ln of 256, you use these keystrokes, IN EXACTLY THIS ORDER:
900 i, 1 PV, 256 FV. Press n to get the answer: 2.408240 is the LOG. Press X<>Y to show the Ln of 5.545177.

For logarithms of other bases, you would use enter the base:
Press Save, 1 - 100 X, then i and 1 PV, the number and FV and press n to get the result. So for a logarithm base 2 of 256, you take 2-1 * 100 ( or simply enter 100) and press i, 1 PV 256 FV and pressing n will yield 8. The Ln of 256 will still be in the Y-Register.

Later financial models do NOT leave then natural log in Y, but will leave the common log in X per the above instructions. For models that use the TVM5, (starting with the HP-92) the 1 in the PV register needs to be changed to negative.

Common (Base 10) anti-logs are simple. Just enter 10 Save and the number and press Y^X to get the antilog of the number.

For Base e, you first need to compute e (2.718281828), by taking 1.000001 to the power of 1 million, then enter the number and Y^X. This only works on the earlier calculators. During the Woodstock era, I think before the HP-67 came out, internal calculations became more precise, so this trick will not produce the correct value for e on later machines. This is fairly easy to remember: Just take 1, the decimal point, add 5 zeroes, and another 1, SAVE, 1000000 and Y^X. Then enter the value you want the anti-log of and Y^X.

Regards,
Bob
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04-19-2015, 09:24 PM
Post: #39
RE: Advice to buy an HP
(04-19-2015 09:11 PM)Cancuino Wrote:  Although I've already bought the HP, I've just read about the TI 89 titanium, is it that good?. I've never tried a TI and want to be sure that the HP is the best choice.

Thanks.

That is a flame war question...
You know the answer here... HP fans support HP calculators for very good reasons!
However, a lot of people that are not particular fans of HP paradigm will prefer the Texas TI-89 Titanium over the HP 50G, also for very good reasons.

Both machines have qualities and defects, and I have yet to find an impartial scientific comparative analysis.

Jose Mesquita
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04-19-2015, 09:25 PM
Post: #40
RE: Advice to buy an HP
(04-19-2015 09:11 PM)Cancuino Wrote:  Although I've already bought the HP, I've just read about the TI 89 titanium, is it that good?. I've never tried a TI and want to be sure that the HP is the best choice.

Thanks.

The TI would be much quicker to learn and likely easier to use initially, but is no comparison when it comes to power, flexibility and the ability to configure and fine-tune the machine to work the way you want it to. Like all things, there are choices and trade-offs. If you're willing to put in the time to learn RPL and the many features and configuration options of the 50g, you will be very satisfied, and in all likelihood, come to rely on and love your 50g.

--Bob Prosperi
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