Casio fxcg 500, FX CP 400

[thenozone]

Science Studio have the FX CP400 for £114.65 plus vat at the moment, a good price for such a calculator, not as fast as some but comprehensive and good precision, haven't found any bugs or irrational behaviour yet, cant say that I have tried everything though, not to many calculators now a days that anyone can say that though.

[Csaba Tizedes]

Turn on Complex numbers, choose Polar form display and type in any negative real number and hit EXE. I'm just curious what you get.

[richmit]

(01-23-2024 07:12 AM)Csaba Tizedes Wrote:  Turn on Complex numbers, choose Polar form display and type in any negative real number and hit EXE. I'm just curious what you get.

How do you "turn on polar form display"?

[Csaba Tizedes]

(01-23-2024 05:58 PM)richmit Wrote:  

(01-23-2024 07:12 AM)Csaba Tizedes Wrote:  Turn on Complex numbers, choose Polar form display and type in any negative real number and hit EXE. I'm just curious what you get.

How do you "turn on polar form display"?

On other CASIOs there is SETUP \ Complex mode \ r<theta, choose this display format, then jump to Main and type eg. (-) 2 EXE

If OS follows the other CASIOs "feature" you will see 2<-180 instead of -2, which is more than a little glitch, this is a huge mistake, try to imagine that student whose no any knowledge about complex numbers. Try to imagine that teacher whose need to instruct students one-by-one to fix this problem.
And try to imagine me, an engineer, how I disappointed when I turned on complex mode and all the negative real numbers are vanished.
Throw these useless sh...ts to the wall and jump on the pieces.

Cs.

[toml_12953]

(01-23-2024 07:12 AM)Csaba Tizedes Wrote:  Turn on Complex numbers, choose Polar form display and type in any negative real number and hit EXE. I'm just curious what you get.

If I type in (-), 5, EXE I get

-5

[ijabbott]

(01-24-2024 06:40 AM)Csaba Tizedes Wrote:  

(01-23-2024 05:58 PM)richmit Wrote:  How do you "turn on polar form display"?

On other CASIOs there is SETUP \ Complex mode \ r<theta, choose this display format, then jump to Main and type eg. (-) 2 EXE

If OS follows the other CASIOs "feature" you will see 2<-180 instead of -2, which is more than a little glitch, this is a huge mistake, try to imagine that student whose no any knowledge about complex numbers. Try to imagine that teacher whose need to instruct students one-by-one to fix this problem.

I got 2∠180 or 2∠π on an fx-9860GII and that is what I would expect to see in r∠θ mode. I would not expect to see −2 because a negative modulus makes no sense (or at least it would not be in the simplest form), mathematically. For what it's worth, HP calculators such as the HP-42S do the same thing.

If a student has no knowledge of complex numbers, then they shouldn't be setting the calculator to that mode!

Going back to the ClassPad II calculators, I don't have any, but looking in the manuals I cannot see any options for changing the default complex display format. However, there are various functions compToPol, compToTrig, and compToRect that will show a complex number parameter in different forms. In radians mode, compToPol will display the number in exponential form \(r\cdot e^{\theta\cdot i}\), otherwise it will display it in polar form \(\angle(r, \theta)\). I suspect that compToPol(−2) would be shown as \(2\cdot e^{\pi\cdot i}\) (radians) or \(\angle(2, 180)\) (degrees) or \(\angle(2, 200)\) (grads).

[Csaba Tizedes]

(01-24-2024 05:03 PM)ijabbott Wrote:  I got 2∠180 or 2∠π on an fx-9860GII and that is what I would expect to see in r∠θ mode. I would not expect to see −2 because a negative modulus makes no sense (or at least it would not be in the simplest form), mathematically. For what it's worth, HP calculators such as the HP-42S do the same thing.

If a student has no knowledge of complex numbers, then they shouldn't be setting the calculator to that mode!

Going back to the ClassPad II calculators, I don't have any...

So, you said, the selected mode is "forced" and not "possibility".
IMHO the -2 is simpler than 2<180.

Try the same in a+bi mode, you will see -2 instead of -2+0i means complex mode in a+bi form is a "possibility" and not "forced".
OR: try +2 in ANY mode and you'll get 2, not 2<0 or 2+0i

Yeah, I know, what you want to say, there is a huge difference between the two mode, is the understanding of the user, and you're right - but you miss a half step as CASIO missed also: between the two settings there is a third, as I want to see the result: reduced as possible: if a complex number has no imaginary part, that is a real, therefore I want to see a real number.

Your meaning means if you want to store a positive integer you must to use always the memory required for a complex number.

"Students" part is also not stands in reality, just try on fx-991EX the quadratics solver with one negative and one positive REAL roots but complex mode on, you will also got the above and try to explain this result to a student.

Cs.

[richmit]

I don't think the Classpad II has a "polar display mode". You can enter numbers in polar or rectangular format. If your computation only has real & rectangular format complex numbers, then the results are rectangular format. OTOH, if your computation contains a polar format complex number, the result is a polar format complex number. In practice this works pretty well. You can force the Classpad II to convert a number to rectangular or polar form with the compToPol or compToRect commands.

As for negative reals, they get displayed as <(-1,180) in degrees mode.

[richmit]

(01-16-2024 09:46 PM)thenozone Wrote:  Science Studio have the FX CP400 for £114.65 plus vat at the moment, a good price for such a calculator, not as fast as some but comprehensive and good precision, haven't found any bugs or irrational behaviour yet, cant say that I have tried everything though, not to many calculators now a days that anyone can say that though.

I have been using the CP400 for several years now, and I have to agree. The software is well designed, logically consistent, and has remarkably few bugs -- I'm only aware of a couple in fact. At first, I was doubtful about the use of the stylus. Now it seems pretty natural, and it really speeds up some tasks.

Be sure and setup the [shift] keys on the physical keyboard as that can really help make the machine more efficient to use.

I just wish the thing was faster. It needs a good ARM processor...

[bxparks]

(01-24-2024 06:40 AM)Csaba Tizedes Wrote:  If OS follows the other CASIOs "feature" you will see 2<-180 instead of -2, which is more than a little glitch, this is a huge mistake, try to imagine that student whose no any knowledge about complex numbers. Try to imagine that teacher whose need to instruct students one-by-one to fix this problem.
And try to imagine me, an engineer, how I disappointed when I turned on complex mode and all the negative real numbers are vanished.

I couldn't believe that a calculator would do this, so I tried it on the fx-9750giii that I got recently, and holy crap, it turns the real number "-2" into the complex number "2∠180". But inconsistently, it doesn't turn the real number "2" into the complex number "2∠0". I think I would be happier if it was consistent. So the expression "2-4" becomes "2∠180". No other (non-Casio) calculator that I know does this, a quick check: TI-83+/84+, TI-89T, HP-42S/Free42, none of them do this.

(01-24-2024 06:40 AM)Csaba Tizedes Wrote:  Throw these useless sh...ts to the wall and jump on the pieces.

Ha, the Casio is still one of the best bang for the buck, and I got other plans for it...

[lrdheat]

My 9750giii OS version 03.70.3200 with -2 produces 2 angle pi. With 2, it simply returns 2.

[carey]

(01-24-2024 07:32 PM)richmit Wrote:  I have been using the CP400 for several years now, and I have to agree. The software is well designed, logically consistent, and has remarkably few bugs -- I'm only aware of a couple in fact.

Yes, the CP400 & CG500 are worthy calculators. If I recall, the founder of the company associated with the Classpad CAS system was a former Tektronix engineer and math Ph.D. Unlike the HP49g/50g which includes only the Laplace transform (symbolic) and FFT (numeric), the CP400/CG500 includes those transforms plus includes symbolic Fourier transforms with 5 notation choices (Modern Physics, Pure Math, Probability, Classical Physics, and Signal Processing)! Based on this and its nice differential equation numerical solver, the CP400/CG500 is a good choice for scientists and engineers who don't mind the large form factor, stylus and modest speed.

[ijabbott]

(01-24-2024 08:45 PM)bxparks Wrote:  I couldn't believe that a calculator would do this, so I tried it on the fx-9750giii that I got recently, and holy crap, it turns the real number "-2" into the complex number "2∠180". But inconsistently, it doesn't turn the real number "2" into the complex number "2∠0". I think I would be happier if it was consistent. So the expression "2-4" becomes "2∠180". No other (non-Casio) calculator that I know does this, a quick check: TI-83+/84+, TI-89T, HP-42S/Free42, none of them do this.

The TI-83/TI-84 will leave "-2" as-is in complex polar mode, but will convert "-2+0i" to polar form. I.e., if it looks real, it will allow it to be negative, but if it looks complex, it will convert it to the current complex mode. The polar mode is actually shown in exponential form, even when the angle mode is degrees, which is somewhat misleading, e.g. "-2+0i" is shown as \(2e^{180i}\).

TI-89 series will convert a complex number with zero imaginary part to a real number, so "-2+0i" is converted to "-2".

HP-42S will happily convert two real numbers in Y and X to a complex number in X according to the current RECT or POLAR mode (although they are always stored in rectangular form), and will display complex numbers in the current RECT or POLAR mode. The modulus is always positive. The "+/-" key will change the argument by π radians or 180 degrees or 200 grad.