using factorial in probability question

[Tim Wessman]

Yup, guess I never had that turned on. Wouldn't surprise me if it is in Prime as well (at least the option to error) as when the math library was rewritten it came from the saturn assembly.

[AlexFekken]

I also agree that it would be good (i.e. I would strongly prefer it) if overflows (and underflows!) would generate errors instead failing silently and returning a misleading value.

[resolved]

"Meanwhile, being aware of how the machine works internally should help avoid unexpected results."

Not to be facetious -- but what resources are available to me to understand the internal working of the HP Prime -- what is it that I "should" know to be able to intelligently use this machine???? -- if it is for me to believe that such knowledge is simply compiled, available and understandable to the average high school / college student, appears ludicrous, then expecting the casual user to know that overflow errors are hidden from them is also ludicrous. How many HP Prime users, off the top of their head could tell you at what factorial the HP Prime hits its upper limit -- none unless they researched it.

The original question I asked was a simple high school statistics problem, which millions of students must study. You don't truly believe they must understand the internal working of the HP Prime before they can do such elementary math????

This is not a judgment of you Joe --- You have been more than helpful and inspiring, but it is a judgment on HP not to be more informative, it almost seems sadistic to set up casual users to such failures.......

Understand that I truly love this machine, I can actually read the screen without fighting the room's light source, but it can still be improved....

[pier4r]

(10-03-2017 06:17 AM)resolved Wrote:  You don't truly believe they must understand the internal working of the HP Prime before they can do such elementary math????

I disagree. If the math is elementary, then try to do it on paper by yourself. 365! computed on paper. Have fun.

If a student has no sense about how large is a number (and the limits of digital representation of it), in this case 365!, a tool won't help.

The tool helps when there is a bit of understanding before, otherwise it is just a quick way to cut corners until it works, and when it doesn't, it is the fault of the tool rather than lack of understanding of the procedure.

And indeed seeing such things as "elementary" is only so because many people are used to tools that do the heavy work for them with little understanding about how "heavy" is this work.
Don't get me wrong, I do the same mistake over and over. Then I learn that I demanded too much and I have to understand the tool better.

Example, if it is that easy: how many digits 365! has? Could you compute it without a computing machine, but only on paper?

[chromos]

(10-03-2017 07:43 AM)pier4r Wrote:  

(10-03-2017 06:17 AM)resolved Wrote:  You don't truly believe they must understand the internal working of the HP Prime before they can do such elementary math????

I disagree...

This, in whole context, is all about the calculator should tell to user that it isn't capable to compute a expression instead of giving some _random_ number as answer.

Do you prefer misleading result instead of information 'sorry, I'm unable process such big number(s)'?

[resolved]

pier4r, you are confusing elementary with easy. Knowing how to use factorials is elementary to math, although it may not be easy to do by hand.

the denotation of elementary is: "of or relating to the most rudimentary aspects of a subject"

synonyms for elementary are: basic, rudimentary, fundamental; preparatory, introductory, initiatory, entry-level

and learning about factorials is elementary in that it is fundamental and preparatory to the learning of other subjects.

in HOME:

200! / 194! = 5.93342...E13 is this answer correct???
253! / 194! = 3.89222...E138 is this answer correct???
254! / 194! = 7.52344...E138 is this answer correct???
354! / 194! = 7.52344...E138 is this answer correct???

how is a user to know when HP Prime has hit a secret overflow value that is hidden from him???? That is the point, not if the math is difficult or easy to do by hand.....but, really, how are users to know that the answer that the HP Prime has given them is a correct answer???? In the example above, you can make a comparison, but in most cases when users are making calculations, they are not making comparisons to determine if the Prime is giving them a correct answer. The confusion increases when CAS and HOME do not confirm each other....

[pier4r]

ah so you mean, instead of giving a wrong answer, prompt something like "error"? On that I agree,

I misunderstood your previous post then.

[luckybuck]

Yes, definitely, HP should update the firmware. Instead of given the same result for 2 or even more different factorials, it would be nice to have:
"out of range"
for example.