28C ISOL - what's wrong?


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)

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

Why 'VG' contained in the answer?

Thanks for any ideas!



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.



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


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

10110 to delete


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


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