Using the given program, you'd enter the four equations and the list of unknowns on the stack:

'V1-V2 = 10*IX'
'V1/(0,20) + (V1-V3)/20 + V2/10 + (V2-V3)/(0,-10) = 0'

'V3/(0,10) + (V3-V2)/(0,-10) + (2,|_-45) + (V3-V1)/20 = 0'

'IX = -V3/(0,10)'

{V1 V2 V3 IX}

In the second equation, |_ stands for the angle symbols (right arrow + SPC). Notice that if your calculator is in rectangular mode, as soon as you enter this equation (2,|_-45) will be automatically converted to rectangular coordinates.

After entering these five objects, just press SYS. The answer will show up in about 15 seconds. It is necessary to press left arrow + EVAL, that is, ->NUM, since the answer will be in a rational form. It will be convenient to identify the section at the end of the program that does this and eliminate it.

If I haven't made any mistake, the answer will be:

V1=(-1.886,-24.513)

V2=(-1.886,-5.657)

V3=(-18.856,0.000)

IX=(0.000,-1.886)

Change the coordinate mode to polar, if you need the answer this way.

You might want to press EQS in the menu, then VIEW, and check if the equations were keyed in correctly.

You should replace IX in the first equation with -V3/(0,10), so that you have to solve a 3x3 system rather than a 4x4 one.

As you can see, there's no need to upgrade your 48G+ just because of this. By the way, I haven't been able to put this program to work in the 49G (perhaps I should also read the manual).

Regards,

Gerson.

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P. S.:

You can copy and paste the program to a file named LSYS, for instance, and then transfer it to the 48G+ (ASCII, cksum=3, translate=2). Or create a directory named 'LSYS' and key in both programs.

Just replace

\<- with <- (right arrow + 0)

Save the first program as '.<-' and the second as 'SYS', in this order.