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HP 50g Simultaneous Equation Solving - Erik Lane - 10-02-2008
I've been trying to get the calculator to solve simultaneous equations, and it's annoyingly slow, especially with regards to the TI-89 of some of my classmates. They can get the answer in 2-3 seconds and mine will take 30-45 seconds. Some it doesn't seem to want to come anywhere close to the right answer. Is there a better solution than the MSLV to do this? For example, 80*cos(30)-T*sin(theta)=0 and 80*cos(30)-T-T*cos(theta)=0 doesn't want to head in the right direction even with the default guesses of 0 for both variables. I assigned units of degrees to the numbers so they would work right. I figured it would whip it out in no time, but it kept going so I interrupted it and just plugged it in by hand. That's a relatively simple one to do that way, but they aren't all so simple. I'm somewhat new to the calculator and have only scratched the surface of what it can do, so maybe I'm going about this all wrong. I would love to hear that because it's embarrassing to still be waiting while the TI crowd has long since had the answer. Also frustrating thinking ahead to exams when I might not have the extra time to wait. (No, I'm not worried about the 45 seconds, but the few different sets of equations that I had to interrupt because they weren't even headed the right way.) I've done a bunch of google searches, I've downloaded different solvers, but I can't seem to get them to work like they should. I get them installed, but then using them is usually not as easy as I expect and it seems like I'm fighting them MUCH more than they're helping me. If there's one I should definitely try out, please let me know.
Thanks in advance!! Re: HP 50g Simultaneous Equation Solving - Damir - 10-02-2008
http://www.hpcalc.org/details.php?id=3145
For: 80*cos(30)-T*sin(theta)=0 and 80*cos(30)-T-T*cos(theta)=0 T = 12.34 and theta = 1.57 time = 5 seconds
With default guesses of 1 for both variables
Regards,
Re: HP 50g Simultaneous Equation Solving - Erik Lane - 10-02-2008
Well, the time that it took is great, but the answers are wrong. Did you put the 30 degrees in as radians? I'm sorry if I didn't make it clear that they were degrees. That's the only reason I can think of why it would give back faulty answers, other than it's not programmed well. But if you regularly use it and like it then it would surprise me if it wasn't a quality program. Should be T=46.2 and theta = 60 degrees, or 1.047rad. You can verify that by doing it by hand, solving the first equation and then putting that number into the bottom one to solve for T. (Although to convert from rad to deg it should be (number in rad)*180/pi not addition.) Either way I will download and try out that solver since it is quick and see if I can make it work for me. Edit: Funny that this is also one I've already tried out, but couldn't get it to work. (One problem was that I was trying so many of them at a time that I got overwhelmed and lost track of which was which and then got frustrated.)
Thank you! I really appreciate the response!
Re: HP 50g Simultaneous Equation Solving - Damir - 10-02-2008
Quote:
Yes,I put the calculator in radians mode.
I use that numbers in first and second equation
Regards,
Re: HP 50g Simultaneous Equation Solving - V-PN - 10-02-2008
I EVALuated the COS(30) in DEGrees mode Exact on (getting \v/3/2) Better to load SolveSys library
Re: HP 50g Simultaneous Equation Solving - Erik Lane - 10-02-2008
I finally figured out why nothing is working out quite right - it was late last night when I was posting, and I didn't give you the correct formula. The first cosine is actually supposed to be sine. Here's the correct formula: 80*sin(30)-T*sin(theta)=0 and 80*cos(30)-T-T*cos(theta)=0 Sorry about that. That will of course affect the calculations just a tiny bit... :) That program at the same link will do it quickly, and even stay in degrees mode? (Kind of a rhetorical question, since I'm going to go download it right now and play with it so I will find the answer out very soon.)
Thank you! Re: HP 50g Simultaneous Equation Solving - Erik Lane - 10-02-2008
Quote: I'm sorry, but I don't understand the shorthand or conventions behind this notation. What does that mean?
Quote: I never had heard of XQ before, but I looked it up in CAT and checked the help on it - it's very useful! That's a wonderful little thing to know, thank you!
Erik
Re: HP 50g Simultaneous Equation Solving - Damir - 10-02-2008
Quote:
Yes!
Regards,
Re: HP 50g Simultaneous Equation Solving - V-PN - 10-02-2008
http://hpconnect.sourceforge.net/trigraphs.html
Re: HP 50g Simultaneous Equation Solving - V-PN - 10-02-2008
Using your 46.2 1.047 and RADians mode
['40-T*SIN(O)' '40*V3-T*(1/COS(O))']
{MSLV}HEAD MEM;TEVAL
If the gusses are far from these
with the unsimplified equations and in DEGrees mode
You need the TI-89 for this kind of problem solving
Re: HP 50g Simultaneous Equation Solving - V-PN - 10-02-2008
I tried SolveSys with RADians mode and simplified equatuations
So you don't need TI after all, SolveSys is enough |