CASIO fx-991CW

[bbergman]

(03-29-2023 09:56 PM)thenozone Wrote:  ... none of the English models I have seen so far have the periodic table that some have been looking out for. ...

As I posted above, the Japanese version is readily available via Amazon, has the Periodic Table function, and can display in English. It's just kinda expensive...

[Csaba Tizedes]

... and multistatement ( : ) missing also.

(03-29-2023 03:16 PM)Csaba Tizedes Wrote:  In the fx-991CW THERE IS NO CALC!!!
You can't evaluate expressions like on 991EX. If someone found it pls post here!

Damn! The most important function is removed...! I want my money back! Without CALC this calculator is useless!

Cs.

update: on fx-880BTG there IS CALC!!!
update2: on fx-991CW the num solver works for variable x ONLY! I don't believe it is happened! Who was that stupid product manager who accepted these things...?!?!?!?

[BINUBALL]

(03-29-2023 03:16 PM)Csaba Tizedes Wrote:  In the fx-991CW THERE IS NO CALC!!!
You can't evaluate expressions like on 991EX. If someone found it pls post here!

Damn! The most important function is removed...! I want my money back! Without CALC this calculator is useless!

Cs.

update: on fx-880BTG there IS CALC!!!
update2: on fx-991CW the num solver works for variable x ONLY! I don't believe it is happened! Who was that stupid product manager who accepted these things...?!?!?!?

On 570CW, num solver can also accept other variable like A, B, C... Which error did you get?

[Csaba Tizedes]

(03-31-2023 12:13 PM)BINUBALL Wrote:  On 570CW, num solver can also accept other variable like A, B, C... Which error did you get?

Sure!
But: define f(x)=Ax+B, then jump to SOLVE and try to solve y=f(x) for A or B...
OK, TI-30X Pro MathPrint also can't handle this.

Cs.

[Csaba Tizedes]

Another bug: STO and RECALL removed. Type in some statistical data. Do statistical analysis, then try to store ANY calculated value (mean, variance, etc...) to variables. You can't. Only via Ans.

[BINUBALL]

(04-01-2023 12:47 PM)Csaba Tizedes Wrote:  Another bug: STO and RECALL removed. Type in some statistical data. Do statistical analysis, then try to store ANY calculated value (mean, variance, etc...) to variables. You can't. Only via Ans.

You can do this. Look at manual p75~p77 for get statistics data, p36~37 for using Variables.

[Eddie W. Shore]

Received my 991CW this morning.

[Eddie W. Shore]

Storing Numbers in Solver

The Solver can solve for any variable, not just x. Store values in other variables through the [VARIABLE] key.

Example: A^2+B^2=C^2

If A = 5 and C = 13, solve for B.

[ HOME ], Equation
Select Solver
Type A^2+B^2=C^2, press [ EXE ]
At the Solve Target screen, select B
Store 5 in A by pressing [VARIABLE], select A, [ OK ], Edit, entering 5, [OK]
(we're back to the variable screen)
Store 13 in C by selecting C, [ OK ], Edit, entering 13, [ OK ]
Press [ undo ] to get back to the Enter Initial Value Screen.
Select Execute to solve for B.

B = 12, L-R = 0




Storing Statistical Results

Again, storing is through the [VARIABLE] key.

Example: Store Σx in E and Σx^2 in F through the following data:

12.3
13.6
14.9
18.8

Enter data in 1-varaible statistics.
Press [ EXE ], select Statistics Calc.

Recall Σx by [CATALOG], Statistics, Summation, Σx, [ EXE ], [ EXE ] (twice)
[VARIABLE], select E, [ OK ], Store (59.6 is stored in E)

Recall Σx^2 by [CATALOG], Statistics, Summation, Σx^2, [ EXE ], [ EXE ] (twice)
[VARIABLE], select E, [ OK ], Store (911.7 is stored in F)

Values stored in variables are retained until cleared by a reset or a new value replaces the old value.


Other

I do miss the ALPHA key and the independent variable M/M+/M-. I would have been nice to store custom functions assigned to the shifted functions of [ × ] and [ ÷ ].

[Csaba Tizedes]

Yeah, the SOLVE can solve for ANY variable if those variables are typed directly. But can't if those variables are come from f() or g() definition as I wrote above.

This storage of statistics registers is not direct storage. Just grab your 991EX and check: you can store these variables like sx STO E, etc... When you press TWICE the EXE, on 991CW you made a copy of VALUE of that stat register. And after this, the copy of value can be stored. This value probably the ANS, must to check.

And multistatement is missing.

Maybe you're more tolerant, I guess, this is come from the cultural differences and you're only collectors, but I'm member of CASIO Educators and I must to look these glitches as backward steps, as a serious user of these machines.

I have 40+ educational video about 991CEX, how you can explain these stupid "updates" if 991EX cancelled and this bad designed "thing" will be use in the schools?!

Cs.

CASIO fx-991CEX - a leghatékonyabb Classwiz Akcióban | CASIO fx-991CEX - the most powerful Classwiz in ACTION: https://www.youtube.com/playlist?list=PL...ons3wS2cef

[Eddie W. Shore]

I tried the f(x) in the solver and I can confirm that the solver does not include the other variables with that method.

As I said before, I prefer the ALPHA key. I will go one step further and advocate that storage arithmetic (like the HP/Swiss Micros calculators) should be included. I think this is the most efficient way to do it.

When the Casios had the multistate command, storing calculations immediately terminated the entry:

pi^2/6 [ STO ] A (terminated)
A^2 / (A + 1)

Ans could be used:

pi^2/6: Ans^2/(Ans+1)

For the fx-115ES Plus (1st or 2nd Edition), we could use both Ans and PreAns.

[Csaba Tizedes]

(04-02-2023 01:48 PM)Eddie W. Shore Wrote:  When the Casios had the multistate command, storing calculations immediately terminated the entry ... Ans could be used ... For the fx-115ES Plus (1st or 2nd Edition), we could use both Ans and PreAns.

Of course you can use the following structure:

Code:

var1=expression1:var2=expression2: ... etc

Then press CALC (which is removed from 991CW )

This is same as STO but without entry cancellation.

Check this video (How to emulate IF...THEN structure on CASIO fx-991EX):

[lrdheat]

I like this calculator! I can define g(x) to be d/dx of f(x), create a table for both to find where extremums are nearby, then use the solver to find g(x)=0, save the solution into, say, A, go to calculate app, enter f(A) to find the extremum! I can find roots of f(x), save them into variables and then integrate from one saved variable to the next to find the area under the curve between roots. Another neat deal is that the calculator uses 17-22 internal digits meaning that the answer will come out to an actual fraction instead of a repeating decimal when the 991EX, or even the fx-CG50 will show the repeating decimal. When integrating an improper integral such as 1/sqrt(x-1) from 0 to 1, the 991EX allows a calculation when the upper end of the interval is 1-1*10^-12. The 991CW allows 1-1*10^-18 to be used, resulting in a much better approximation for such an integral. One needs to download the manual to understand how to access/enter functions, but it is easy, makes sense rather quickly. I like that f(x), g(x) is accessible in the calculate app. The stats app is good as well as the distribution app. Still much more to explore!

[lrdheat]

I meant integral from 0 to 1 of 1/sqrt(1-x). The answer using upper end as 1-1*10^-18 comes out as 1.999999998 which is very close to the answer of 2.

[Eddie W. Shore]

My review of the Casio fx-991CW: http://edspi31415.blogspot.com/2023/04/r...multi.html

The original post is no longer available, this is the updated link (4/12/2023).

[Csaba Tizedes]

And what is your opinion/advice for CALC? Maybe TABLE? But TABLE works only if you define f() or g() and you lost actual f() or g(). The CALC asked each variables during calculation, TABLE is not, like SOLVE also, it is required to type each variables one-by-one in Variables menu...Clumsy... Not straightforward.

[ijabbott]

(04-04-2023 05:21 AM)Eddie W. Shore Wrote:  My review of the Casio fx-991CW: http://edspi31415.blogspot.com/2023/04/r...991cw.html

Nice, quick review. Thanks!

BTW, has your dog been chewing your fingers?

[pier4r]

if someone has willing and has spare time, one could try the summation benchmark here: https://www.hpmuseum.org/forum/thread-9750.html

[Eddie W. Shore]

(04-04-2023 08:29 PM)ijabbott Wrote:  

(04-04-2023 05:21 AM)Eddie W. Shore Wrote:  My review of the Casio fx-991CW: http://edspi31415.blogspot.com/2023/04/r...991cw.html

Nice, quick review. Thanks!

BTW, has your dog been chewing your fingers?

Thank you. No, it's a paper cut.

[Eddie W. Shore]

(04-04-2023 09:04 PM)pier4r Wrote:  if someone has willing and has spare time, one could try the summation benchmark here: https://www.hpmuseum.org/forum/thread-9750.html

Casio fx-991CW:

Σ( ³√[e^(sin(tan^-1(x)))], x=1 to 1000)

Result: 1395.346288
Time: approx. 57 seconds

I posted the result on the benchmark thread.

[Csaba Tizedes]

(04-04-2023 05:21 AM)Eddie W. Shore Wrote:  My review of the Casio fx-991CW: http://edspi31415.blogspot.com/2023/04/r...991cw.html

Quote:There is no longer the ability to use multi-statement expressions, with each expression separated with a colon. Even when it was available, (1) storing results immediately terminated the expression (forcing the use of Ans and when available, PreAns to make using results in the next part possible), and (2) when replayed, the statement was broken up into separate parts.

This is true, but you use multistatement in wrong way. And you do not checked the linked video Just few minutes and you can see multistatement how efficient. AND I'm sure if you try, you will surprised how easy to expand the possibilities and add an IF/THEN structure for a non-programmable calculator.

Just try it:

Code:

Type in C=A+B:D=C/2
press [CALC]
Type something for A and B, eg. 7 [EXE] and 3 [EXE], then you can see value of C, then [EXE] again, you can see value of D.
At this point, you can edit the WHOLE expression, just press [left] and you will get the original C=A+B:D=C/2 multistatement for edit.

Cs.