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Honor Student
Posts: 2
Member Since: ‎02-14-2014
Message 1 of 4 (908 Views)

# HP prime

First off let me start by saying it's great to finally see HP providing a CAS to compete against Nspire, I hope the future will bing Mac versions of emulator, and connectivity  kit.

My question relates to Solve where on the Nspire you could type a formula using only variables, and and solve for solutions, a simple example could be law of ohm where Solve(u=r*i,i) would output i=u/r.

a similar attempt on the prime gives me Solve(0=0,0) Am I using the Solve() function wrong, and can this be done on the prime??

# Re: HP prime

Hi!, jj2005:

Welcome, to Forum!.

Go to CAS view, then type in ...

solve(your_equation, your-variable)

solve(u=j*r,j)

Where ... for Ohm law ...

u = Tension, in VAC.

j = Intensity of current, in Amperes.

r = Resistance, in Ohms.

There is, the answer ... {u/r}

Caution: ... "i" ... it is, for reserved (complex) ... so use something, different instead. You can use "j" or other's.

View solution in context
Professor
Posts: 2,644
Member Since: ‎02-17-2015
Message 2 of 4 (856 Views)

## Re: HP prime

Hi!, jj2005:

Welcome, to Forum!.

Go to CAS view, then type in ...

solve(your_equation, your-variable)

solve(u=j*r,j)

Where ... for Ohm law ...

u = Tension, in VAC.

j = Intensity of current, in Amperes.

r = Resistance, in Ohms.

There is, the answer ... {u/r}

Caution: ... "i" ... it is, for reserved (complex) ... so use something, different instead. You can use "j" or other's.

Welcome, to this Forum !.

Thank you soo much, by trusting in HP !.

Top Contributor (Gold 2016) - Expert Provost, in Spanish Forum (http://h30467.www3.hp.com) and HP Expert Program Top Contributor #HPMeetup17.

Kind Regards.
Maké.
Honor Student
Posts: 2
Member Since: ‎02-14-2014
Message 3 of 4 (799 Views)

## Re: HP prime

Thanks a lot, the error was not very explaining, Does anyone knows of a list of all variables that are not useable???

Posts: 360
Member Since: ‎02-04-2014
Message 4 of 4 (786 Views)

## Re: HP prime

> Does anyone knows of a list of all variables that are not useable???

Yes: Nothing in the Toolbox Catalog (e.g. i , which is at the very bottom of the list) can be used as a variable, because all of these are PPL commands.  Also, nothing in the Program Editor's menus (Cmds and Tmplt) can be used as variables (e.g. KEY) because those are also PPL commands (although only used for programming).

You should also never use upper/lowercase variations on PPL commands as variables.  For example, Prime allows you to store into a CAS variable named "To", but that causes Prime to get confused when it executes the TO command.

So before creating any CAS variable, check the catalogs to see if it's a PPL command or an upper/lowercase variation of a PPL command.

Also, some variables are permanently defined by Prime and cannot be deleted, although their values can be changed.  I'm attempting to maintain a complete list of all the built-in variables HERE.

Hope that helps!

-Joe-
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