HP Forums
Easy question about System of equations solver - Printable Version

+- HP Forums (https://www.hpmuseum.org/forum)
+-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html)
+--- Forum: HP Prime (/forum-5.html)
+--- Thread: Easy question about System of equations solver (/thread-6174.html)



Easy question about System of equations solver - PedroML - 04-29-2016 07:54 AM

Hello, here a newbie using HP Prime, Thank you for your attention.

As I am using solve() for getting the solutions of a simple polynomical system, it provides 2 pairs of solutions. The question is, how can I store each of them wihtout retyping?.

Maybe the attached screenshot will help to understand the question.
ScreenShot

Thank you in advance.
Pedro ML


RE: Easy question about System of equations solver - primer - 04-29-2016 08:01 AM

you can copy the list to a variable,
Code:
Ans▶L1
and then ask for 1st solution :
Code:
L1(1)
and for the 2nd :
Code:
L1(2)



RE: Easy question about System of equations solver - DrD - 04-29-2016 09:32 AM

This also works:

L1:=solve({2*x^2+3*y^2 = 1, 2*x+3*y = 1},{x,y})

L1(1) ==> [-0.29 0.53]
L1(2) ==> [ 0.69 -0.13]]


RE: Easy question about System of equations solver - PedroML - 04-29-2016 09:49 AM

I see, thank you!
As L1 is a list and elements are matrix 1x2, then I need:
L1(1)▶M1
L1(2)▶M2
and I can use M1(1,1), M1(1,2), M2(1,1), M2(1,2)

Is that right?


RE: Easy question about System of equations solver - DrD - 04-29-2016 10:04 AM

(04-29-2016 09:49 AM)PedroML Wrote:  I see, thank you!
As L1 is a list and elements are matrix 1x2, then I need:
L1(1)▶M1
L1(2)▶M2
and I can use M1(1,1), M1(1,2), M2(1,1), M2(1,2)

Is that right?

M1 is a vector in this case, with size(M1) == 2. So elements of the vector are:

M1(1) == -0.29
M1(2) == 0.53

M2(1) == 0.69
M2(2) == -0.13

When:
L1:={[-0.29 0.53], [0.69 -0.13]};
L1(1,2) ==> 0.53 (For example, to reach the second element of the first vector, as a one dimensional array, in a list of vectors).

As a vector, there aren't any rows and columns, its just a one dimensional array. M1(row, col) works for matrices. Lists, vectors, and matrices are a subject that could stand additional clarification in the user references. Lists and vectors have a lot in common. The solve() command is one particular example. For instance, if you try the examples given in the calc Help, some return lists, and others return vectors. The Help detail says the command "Returns a list of the solutions..."


RE: Easy question about System of equations solver - PedroML - 04-29-2016 11:21 AM

Thank you both, got it!!!
So quickly all answers. Great.