In RPL, is there a way to integrate (S) on a program <<...>> integrand ? I don't think so,

Something like this :

0

1

<<X SIN X SQ - >>

'X'

S

where the legal way to integrate is :

0

1

'SIN(X)-SQ(X)'

'X'

S

a program gives sometimes more flexibility to build a function to integrate.

(08-05-2021 12:52 PM)OlidaBel Wrote: [ -> ]In RPL, is there a way to integrate (S) on a program <<...>> integrand ? I don't think so,

Something like this :

0

1

<<X SIN X SQ - >>

'X'

S

where the legal way to integrate is :

0

1

'SIN(X)-SQ(X)'

'X'

S

a program gives sometimes more flexibility to build a function to integrate.

Try writing the program as a "user-defined function" which means storing the argument(s) in local variable(s) like this:

<< -> X << X SIN X SQ - >> >>

or

<< -> X 'SIN(X)-X^2' >>

RPL treats programs like that more like built-in functions when solving, graphing, and so on, so it might help here too.

(08-05-2021 01:27 PM)Joe Horn Wrote: [ -> ]Try writing the program as a "user-defined function" which means storing the argument(s) in local variable(s) like this:

<< -> X << X SIN X SQ - >> >>

or

<< -> X 'SIN(X)-X^2' >>

RPL treats programs like that more like built-in functions when solving, graphing, and so on, so it might help here too.

Unfortunately something like this is refused on HP 48GX :

0

1

<< -> X 'SIN(X)-X^2' >> or << -> X << X SIN X SQ - >> >>

'X'

S

=>

"S Error:

Bad argument type"

I checked the old HP-28s documentation. This calculator was more permissive with S.

But this is accepted :

EQ = 'EQ1(X)'

EQ1 = << -> T << T SIN T SQ - >> >>

0

1

'EQ1(X)'

'X'

S

=>

0.12636

You can use

\<< <-X SIN <-X SQ - \>> 'F' STO

0.

1.

'F'

'<-X'

S

with <- the backarrow symbol, declaring a local variable.

If you don't like that, you'll have to do it the way Olidabel did

Cheers, Werner

Thanks Joe & Werner,

I finally succeeded (and understood!) how to play with integrals S onto programs. I could adapt my old 28S program and results are now OK.

The 48GX is definitely different than a 28S, it was not easy to troubleshoot ;-).

Starting with an algebraic expression and playing with local variables in <<...>> was the key.