Problem with 2nd order polynomial

[ktomp]

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

[Patocuy]

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

[ktomp]

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.

[C.Ret]

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!

[Liamtoh Resu]

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.