[VA] SRC #017 - April 1st, 2024 Spring Special

[J-F Garnier]

(04-01-2024 06:59 PM)Valentin Albillo Wrote:        As we have that  GCD(15, 4) = 1  and  GCD(15, 5) = 5,  for what value of x is  GCD(15, x) = 2 ?

OK, let's try to solve GCD(15,X)=2 for X on the 71B w/ Math ROM.
Since GCD only accepts integer values, I had to cast the X variable to the INT type.
Choosing 0 and 10 as the initial guesses:

>FNROOT(0,10,GCD(15,INT(FVAR))-2)
12.9999999999

We can safely round the result to X=13.
An interesting result, isn't it?

Quote:[*] [HP-71B specific] Try and deduce what result will be output by this expression without actually executing it: some regular numeric value ? Perhaps Inf or NaN ? An error message ? A long-running or indefinite internal loop ?

      NEIGHBOR(INTEGRAL(FNROOT(EPS,EPS,EPS),EPS,EPS,EPS),GAMMA(EPS))

I miserably failed to predict the result !
But I learnt something about the 71B solver...

Quote:[*] [HP-71B specific] I executed this command-line expression on my HP-71B but it just resulted in System Error. What did I do wrong ? Bad addresses ? Forbidden range for PEEK$ ? Can you find out what's wrong ?

      FOR I=64204 TO 64215 @ DISP CHR$(HTD(REV$(PEEK$(DTH$(2*I),2)))); @ NEXT I

Ah ! Nothing wrong, I even didn't need to try ...
      

Quote:[*] [HP-71B specific] What does this HP-71B user-defined function compute ?

      10  DEF FNC(M,N)=M!/N!/(M-N)!

It doesn't do much, I'm afraid.

Quote:[*] [HP-71B specific] The HP-71B does not allow for variable names beginning with a 2-letter or more prefix (e.g. AB, CD7, MYTAXES, etc.) as many other pocket computers do, but executing this assignment in a program or from the keyboard ...

      FORM=STOP

... doesn't result in a Syntax Error so what gives ?

Ah! another new "hidden feature" of the 71B ?

I well remember the undocumented MEMORY function, that accepts up to 2 parameters, but isn't that useful (do first DESTROY ALL to get consistent results):
>MEMORY(1,2)
1


More results later...

J-F