28C ISOL - what's wrong?

[Tizedes Csaba [Hungary]]

Hello, I tryed to isolate a variable from this simply equation (it was late at night, and my brain was VERY slow), but I waked up in that minute, when answer appeared on 28C's LCD:

'S=(VG-VA)/VG'  (definition of slip in pneumatic conveying vg: speed of gas, va: speed of coveyed material)

'VG'

Then I pressed [ISOL], and the answer was 'S*VG+VA'

Why 'VG' contained in the answer?

Thanks for any ideas!

Csaba

[ned]

I believe the problem is due to the fact that isol only works for one instance of a variable. In other words, isol will not behave as a 'symbolic solver'. I tried your problem on my 48g+, which results in an error message. Perhaps the 28c, lacking the user interface shell of the 38/48, simply did the best it could, treating the second instance of the variable VG as unique.

-Ned

[Karl Schneider]

This problem produces an error on the 48G, as Ned found out. However, the 49G handled it fine, as I'm sure the 49G+ does (when the keyboard works properly).

Of course, I could have doen that easy algebra problem on paper in the time it took me to have the 49G do it.

-- KS

[Tizedes Csaba [Hungary]]

The better way: RTFM. I'd found the answer... ;)
Cs.

10110 to delete

[Arnaud Amiel]

What it TFM saying? Mine is in German so not very useful...

Arnaud