Discussion in 'Electronic Basics' started by Jack Crane, Nov 25, 2004.

1. ### Jack CraneGuest

What does the Rnd key (SHIFT 0) (in the lower-left corner) on the Casio fx-
115MS calculator do, and how is it used?

And is there anywhere on the web a better manual than the one that comes
with the product? Or a tutorial?

Thanks,

Jack

2. ### Jonathan KirwanGuest

It produces a "random" number.

Jon

3. ### Steve EvansGuest

It rounds off the internal value contained in the Y-register so it
equals the displayed value.

4. ### Jack CraneGuest

Could you give me an example that includes the keys to push?

Thanks,

Jack

5. ### Jack CraneGuest

From what range? The Rnd# key gives a random number in (0,1).

Jack

6. ### Jonathan KirwanGuest

Woops! I got the key next to it! You said, Rnd! My mistake!

Jon

7. ### Jonathan KirwanGuest

Yup! I was looking down at the calculator and looked for shift-0 and instead
saw shift-. My mistake. Actually, I don't recall ever using Rnd, which is
probably why I so quickly assumed I picked out the right key. Sorry about that.

Jon

8. ### Jack CraneGuest

Apology accepted.

Jack

9. ### Steve EvansGuest

I guessso, but its rather late now where I am. I'll do it ifircall
tomorrow.

Great!

Jack

11. ### Steve EvansGuest

Well here I amagain. Your calculator has three main registers for
holding current values, X, Y, and K registers. they each have three
particular jobs to do. X is the working reg., holding the displayed
value, Y's like a variable reserve reg. for any ohter 'reserve' value
and K holds fixed, programmable values. If you divide 50 by 10 then
press <shift><x-y> you'll get the result 0.2 ratger tgan 5. Fool
around with these registers and the RND function and yo';ll see what
goes down. BTW, if you don't know what it does, why do you need to use
it?
Have fun.

12. ### Robert MonsenGuest

Try this sequence:

PI = sin ans

you get zero.

Now, try

PI rnd = sin ans

you get 3.59n (or 3.59e-9)

The rnd rounded PI to the digits on the display, so the answer wasn't
exact wrt the internal registers.

I can't think of a good use for this key. You almost never care about
more than a few significant digits anyway.

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.

13. ### Jack CraneGuest

So why don't you just tell me what RND does?

BTW, if you don't know what it does, why do you need to use
Is that a joke? If not, what do you mean? If I knew what it does, I might
or might not find it useful. If it is useful to me, then I need it.

Jack

14. ### Jack CraneGuest

OK, in RAD MODE I pushed SHIFT-PI, =, sin, ANS, and got 0. That's fine.
I pushed SHIFT-PI, SHIFT-Rnd, =, sin, ANS, and got 0 again, not your
3.59n. Do you have the fx-115MS?
Thanks for trying to help.

Jack

15. ### Robert MonsenGuest

Sorry, I got the directions wrong, you need to put the value PI into the
internal registers before you hit shift rnd. So, try this:

shift PI = (puts it into the register)
shift rnd (rounds register to whats on the display,
subtracting some delta)
sin ans = (computes sin(PI - delta))

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.

16. ### Jack CraneGuest

Ok, got it. Thanks.

BTW how did you learn this? I've found online PDFs of both sheets that came
with my calculator, and that constitute its manual. They are at
<ftp.casio.co.jp/pub/world_manual/ edu/en/fx100MS_115MS_E.pdf>

And

<http://ftp.casio.co.jp/pub/world_manual/edu/en/fx115MS_991MS_E.pdf>

And Rnd is mentioned in neither of them.

I'm now trying to figure out CALC. Could you take a look at the PDF of the
second link I've quoted (or at your calculator's manual)? The CALC Memory
section is on page 6 of the PDF. The example there doesn't work correctly
for me. When I finish entering the function the screen shows "x-cubed + 3x
- 12", which looks good. Then I push CALC and answer "7" for the "x?"
prompt. I get 352 (instead of the correct 58). And for x=8 I get 524 (not
76). Any ideas?

Thanks,

Jack

17. ### Steve EvansGuest

Really? Mine is obtained by pressing <shift><X^2> But I use the
fx-3400P which may differ in some respects. I assumed mine was just
hte programmable version of yours, but the differences might go wider,
I dunno.
Robert and me have already told you that.
Fair enough.

18. ### Chaos MasterGuest

Jack Crane is, and always will be:
I think it stands for 'round number'.

I have not had a Casio calculator for a long time, but AIUI and IIRC it
works like:

3.5683927835
3

RND

3.568

(rounding 3.5683927835 to 3 decimal)

--
Chaos Master®, posting from somewhere near Porto Alegre, Brazil.
"... one either has a shit, or not. Do you have yours?"
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
http://marreka.blogspot.com --> news, hotter than high-power transistors!

NP in foobar2000: 15. Evanescence - [Fallen #05] Haunted [3:07]

19. ### Robert MonsenGuest

7^3 = 343
3x7 = 21

so

343 + 21 - 12 = 352

Sounds like you are doing it right...

Now, try to figure out 'solve'.

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.

20. ### Jack CraneGuest

Oops. Thanks for checking this. In dim light with dimming eyes, from the