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HP Forum Archive 21

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HP-PRIME CAS SOLVING
Message #1 Posted by fabrice48 on 19 Oct 2013, 11:55 a.m.

I have an HP48 with it i solve some expression, but on HP-PRIME, i don't find how to do the same :

example : i have the electrical : U=R*I i want to 'transform it' in CAS style,

ON HP48 i do this : 'U=R*I' 'I' ISOL

then the calculator answer : I=U/R

How to do this on PRIME ????

      
Re: HP-PRIME CAS SOLVING
Message #2 Posted by Helge Gabert on 19 Oct 2013, 12:13 p.m.,
in response to message #1 by fabrice48

Try solve(u=r*ii, ii) gives [ii=(1/r)*u]

I used the CAS do to this, and ii (because i is allocated (complex!)).

            
Re: HP-PRIME CAS SOLVING
Message #3 Posted by fabrice48 on 19 Oct 2013, 12:19 p.m.,
in response to message #2 by Helge Gabert

it's very strange, i do the same as you but my machine answer this : {} have you an idea ?

                  
Re: HP-PRIME CAS SOLVING
Message #4 Posted by fabrice48 on 19 Oct 2013, 12:22 p.m.,
in response to message #3 by fabrice48

i know why :

teh rule seems in CAS only lower cas character allowed.

                        
Re: HP-PRIME CAS SOLVING
Message #5 Posted by Helge Gabert on 19 Oct 2013, 12:26 p.m.,
in response to message #4 by fabrice48

Yes!

                              
Re: HP-PRIME CAS SOLVING
Message #6 Posted by Helge Gabert on 19 Oct 2013, 12:38 p.m.,
in response to message #5 by Helge Gabert

Now I have a question.

I'm running the same command again, from the CAS history,

and my output is in a different format, in curly brackets and without the equal sign and the variable to solve for.

{(1/r)*u}

I didn't change any flag settings (that I'm aware of). ????

                                    
Re: HP-PRIME CAS SOLVING
Message #7 Posted by Han on 19 Oct 2013, 1:22 p.m.,
in response to message #6 by Helge Gabert

Quote:
Now I have a question.

I'm running the same command again, from the CAS history,

and my output is in a different format, in curly brackets and without the equal sign and the variable to solve for.

{(1/r)*u}

I didn't change any flag settings (that I'm aware of). ????


I believe this is normal behavior (the HP Prime does not do everything in the same way as older calculators)

                                          
Re: HP-PRIME CAS SOLVING
Message #8 Posted by Helge Gabert on 19 Oct 2013, 1:35 p.m.,
in response to message #7 by Han

Yes, but when I first ran the command solve(u=r*ii, ii)on the Prime (CAS view) I got this:

[ii=(1/r)*u]

Now I get this on the exact same machine, with the same command solve(u=r*ii, ii), again in CAS view:

{(1/r)*u}

Strange.

What output format do you get?

                        
Re: HP-PRIME CAS SOLVING
Message #9 Posted by Han on 19 Oct 2013, 1:21 p.m.,
in response to message #4 by fabrice48

Quote:
i know why :

teh rule seems in CAS only lower cas character allowed.


The upper case single characters are actually built-in variables. Upper-case variables such as MYVAR is fine.


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