50g Multiple equation Solver (MES)

09282017, 03:21 PM
(This post was last modified: 09282017 03:38 PM by LGVE.)
Post: #1




50g Multiple equation Solver (MES)
I was reading about MES in the HP 50g User's Guide and tried the example of solving triangles ( page 7 9) on my calculator. It worked fine but when I tried to solve a triangle problem, one of the sides was negative. The data:
a=20 alpha=45 degrees betha=60 degrees I press White key with left arrow and ALL I press Orange key with right arrow and ALL The calculator gives as answers: phi=75 degrees b=24.49 c=7.32 c must be positive. Any suggestions? Thanks in advance Luis 

09282017, 05:28 PM
Post: #2




RE: 50g Multiple equation Solver (MES)
(09282017 03:21 PM)LGVE Wrote: I was reading about MES in the HP 50g User's Guide and tried the example of solving triangles ( page 7 9) on my calculator. It worked fine but when I tried to solve a triangle problem, one of the sides was negative. The data: The last value is comuputed probably from the cosine's law C^2=A^2+B^22*A*B*cos(gamma) Being quadratic, the solver might converge to either of the roots, with no easy way to persuade it to go the other way. One way is to provide initial guesses for A,B,C in the positive region (like 10). It might help it stay on the positive side but there's no guarantee. So try again by setting B=10,C=10 as initial data, then solve for them too. 

09282017, 06:16 PM
Post: #3




RE: 50g Multiple equation Solver (MES)
Thanks for your reply Claudio.
Setting b=10 c=10 and solving each variable individually works fine. If I try to solve all variables at the same time using White key with left arrow and ALL and Orange key with right arrow and ALL, it doesn't work. Luis 

09282017, 08:24 PM
Post: #4




RE: 50g Multiple equation Solver (MES)
If you may be a frequent MES user, it might be worth fo you to check SolveSys49. The latter is more convenient than the HP50g stock MES for me, you get to the results in less time:
http://www.hpcalc.org/details/3145 Hope this helps. Saludos Saluti Cordialement Cumprimentos MfG BR + + + + + Luigi Vampa + Free42 LeaGooM9 '<3' I + + + 

09282017, 11:29 PM
Post: #5




RE: 50g Multiple equation Solver (MES)
Hi LGVE,
I had no problem using MES on my 50g. I got b=24.49 c=27.32 So I started messing around putting numbers in b and c and that caused the 50g to display c as a negative number (7.) I then went thru all the examples on page 717 and now it's working again. I also ran MINIT from my home directory. maybe a glitch in the software??? Try this out and see if it helps you. Jim' 

09292017, 07:38 AM
Post: #6




RE: 50g Multiple equation Solver (MES)
Hello,
unfortunately SolveSys49 does not handle units. If you are looking for an easy way to handle the MES than GUIMES might come in handy. Leaving a value in a field is treated as an initial guess, so if the solver might converge to a root that your are not looking for this can be used to point the solver in the right direction. HTH, Andreas http://www.software49g.gmxhome.de 

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