Problem with 2nd order polynomial
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09-18-2024, 08:19 AM
(This post was last modified: 09-18-2024 09:05 AM by ktomp.)
Post: #1
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Problem with 2nd order polynomial
Hello everyone,
I got an exam the other day and to my surprise my HP prime (G1 hardware) failed to solve a 2nd order polynomial (a*x^2+b*x+c = 0) with the following coefficients: a = 30188156.0038281 b = -12497373621.6526 c = 1058636761186.350 I was in CAS mode and tried using the Solve, Zeros, Numerical Solve but only got empty brackets as a result (like []). Same thing happens even with the latest update of 2024/09. It's probably due to the fact that the coeffecients of the polynomial where quite large numbers, cause when I divided everything with the "a" coefficient and the polynomial became x^2+(b/a)*x+(c/a) all the functions managed to find the roots correctly. Could this be a bug? Many thanks for your help |
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09-18-2024, 01:16 PM
(This post was last modified: 09-18-2024 08:37 PM by Patocuy.)
Post: #2
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RE: Problem with 2nd order polynomial
Hi.
I used proot and solve and got the same solutions with both functions, perhaps solve needs to know which variable you are solving for. UPDATE Now I used the same syntax as you, without specifying the variable to solve for and got the same solutions as before. You could use purge(x) to be sure that x has no value assigned and check your CAS settings, I have attached mine so you can compare. Regards |
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Yesterday, 06:58 AM
Post: #3
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RE: Problem with 2nd order polynomial
Hi, thanks for trying to help me out.
I only managed to get solutions with proot() function. Solve() won't return solutions regardless of the syntax. I even purged x just to be sure, but to no avail. |
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Yesterday, 02:53 PM
(This post was last modified: Yesterday 03:03 PM by C.Ret.)
Post: #4
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RE: Problem with 2nd order polynomial
Hi guys!
Just look at this and compare: What are your conclusions or assumptions? Are they the same as the one I just made? How did the CAS-solve statement work out numerically compared to other specific and only numeric functions? Did you understand what happened with CAS-solve when an interval is given for the numerical variable x? Why this works in the first case? Hope this helps you a little. And that the prankster HP Prime didn't ruin all of ktomb 's hopes of passing his exam! |
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Yesterday, 06:16 PM
Post: #5
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RE: Problem with 2nd order polynomial
I have been trying to understand this thread.
How can the estimates for x be obtained without running proot first? There are significant differences of values for 'c' in the two images b C.Ret. Why are there differences between the two solve answers. What are the answers to the questions that C.Ret posed? I hhave limited experiences with the type of problem that ktomb asked on the prime. Thanks. |
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