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From: Roman Hartmann on 18 May 2007 07:35
Hi,
I'm trying to solve a system of equations with MSLV and am wondering if
I can tell MSLV to use some boundaries for certain variables.

Example: D=a*E^b*exp(c*E)
I know 3 values for D and I know that a > 0, 0<b<1 and c<0 and I'm
trying to get the values of a, b and c. E is a number and not the
e^x-function.

In RPN-mode I did the following:

['19.675=a*1.35^b*e^(c*1.35)' '44.05=a*2.83^b*e^(c*2.83)'
'31.49=a*3.3^b*e^(c*3.3)']
['a' 'b' 'c']
[10 .9 -0.1 ]
MSLV

Usually that does work nicely -if the start values are not too far off-
but in this case the equations with the e^x in are a bit too much for
MSLV (BTW, I'm trying to solve that on a HP50G). 'assume(a>0)' seems to
influence only the CAS-settings but does not seem to help the numeric
solvers.

Is there a way to make MSLV use boundaries for certain variables? Or is
there maybe a third party application which does what I'm looking for?

PS: Don't bother to solve the example above for me as I already have all
the numbers I need to draw the curve (for those who try anyway: take
care as MSLV is a real battery hog ...). I just would like to be able to
use the HP50G to draw a curve to check my results quickly. I don't have
the time to simplify the equations with substituting unfortunately.

PS2: For some reasons variable b in the given example isn't between 0
and 1. MSLV reports it to be 7.26.. Could be a units problem in my
particular example or just wrong data.

best regards
Roman
From: Roman Hartmann on 18 May 2007 14:29
Roman Hartmann wrote:
> Hi,
> I'm trying to solve a system of equations with MSLV and am wondering if
> I can tell MSLV to use some boundaries for certain variables.
.....

Ok, seems what I was looking for is SolveSys by Sune Bredahl (was
actually already installed on one of my old HP49Gs). Works like a charm.
Great stuff Sune!

Roman
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