50g

I have brought up the numeric solver, (rt shift + 7), and selected the
solve equation option.

The following displays:
eq: 'V=I*R'
v:
I:
R:

I can enter the variables and solve this equation just fine. If I use
choose, I get a long list of memory contents. If I edit the 1st line
it shows 4 ohms law formulas-

{ 'V=I*R' 'P=V*I' 'P=I^2.*R' 'P=V^2./R' }

I see this as a list of equations for ohms law and the first on in the
list is the one that comes up when starting. My question is how do I
change to the second or third formula in the list or is it possible to
do so. I bought the 50g used and it's possible that the previous user
entered this equation.

I tried reading about this in the advanced user guide but it only
covered inputting a new equation and did not cover having a list. Any
help would be appreciated.

Thanks,
Ron

> { 'V=I*R' 'P=V*I' 'P=I^2.*R' 'P=V^2./R' }
>
> I see this as a list of equations for ohms law and the first on in the
> list is the one that comes up when starting. My question is how do I
> change to the second or third formula in the list or is it possible to
> do so. I bought the 50g used and it's possible that the previous user
> entered this equation.

You'd have to delete the first one manually using edit and then it
would show.

However, I can tell you with 100% certainty that the previous owner
didn't enter those in. They were using the equation library. If you
press APPS and scroll down, you will probably see at number 13 or 14
"Equation Library". (if you don't find it, install the library from
here: http://www.hpcalc.org/details.php?id=6515) Select that, then
press F1 for EQLIB then F1 again. You will now be in a full screen
browser.

Move to electricity, press ENTER, then Ohm's Law and power, you can
now use the up and down arrow to view the equations in this set, VARS
will tell you what they are, etc.

Once ready, press SOLV. Now now you will see V I R P and ALL on the
menu. Type 120 and hit V. Notice the units are automatically
assigned. Hit 20 and I. Then press left shift P. After a second,
your W will pop out.

In other words, it iterates through the equation set, solving as you
go along, and keeping the units straight as you go!

Chapter 5 of the AUR details all of the equations and everything else
you'll find in the equation library. Other usefull commands in
relation tho this are MINIT (initialize MES) and MSOLVR (return to old
previously setup MES).

TW

Thanks again Tim,
That was exactly what I thought, (having to delete or rearrange the
formulas). If I'm guessing correctly, the numeric solver is for
creating a 'quick' solver on the fly.

I have used the "Equation Library". Much more flexible.

I have an advanced users manual for the 48gx somewhere. How different
would that manual be for the 50g?

Ron

> That was exactly what I thought, (having to delete or rearrange the
> formulas). If I'm guessing correctly, the numeric solver is for
> creating a 'quick' solver on the fly.

Generally it is used for solving a single unknown in a single
equation. You can also write something like 'FUNC(X,Y)=X^2+Y' and hit
the DEF key (2) to define a little function solver that takes stack
input. When you define a function to graph, one is automatically
created for you. How handy!

There is one additional solver in the 50 not in the 48s. This is the
MSLV command which is a non-linear series numerical solver. Takes a
lot of inputs though and is kind of slow. Worked great at number
crunching for my statics/dynamics though. Then I discovered matrices
and could solve everything in one go. :-)

> I have an advanced users manual for the 48gx somewhere. How different
> would that manual be for the 50g?

They lifted several chapters directly out of it for the 49/50AUR.
Just remember the CAS only likes to be in radians, and a plain number
without a dot '5 vs 5.' is a symbolic integer and you'll be fine.

I don't remember correctly if the equations library solver on the 48
solved units as well. . .

TW