cancel
Showing results for 
Search instead for 
Did you mean: 
danvail
New member
3 1 0 1
Message 1 of 4
610
Flag Post

HP Prime not able to solve system of equations

HP Recommended
HP Prime

I'm running an HP Prime on the newest firmware version, and went to solve the following system of equations in the solve app:

1.) X=3*Y-9

2.) X*Y=5670

 

After inputting the values and going to the solve numeric view, pressing Solve results in a message saying "Cannot find solution". I've verified that this solution is solvable with the solution (Y=45, X=126). Can anyone explain why the Prime can't solve this, or if I'm doing something wrong?

0 Kudos
Tags (1)
3 REPLIES 3
Maké
Level 9
3,551 3,490 180 541
Message 2 of 4
Flag Post
HP Recommended

Hi!, @Danvail :

See the images and compare with Wolfram Alpha ...

Solve_1.PNG

In CAS MODE, select Exact.

Solve_2.PNG

 

Kind Regards !.
Have a nice day !.
@Maké (Technical Advisor Premium - HP Program Top Contributor).
Provost in HP Spanish Public Forum ... https://h30467.www3.hp.com/
danvail
Author
New member
3 1 0 1
Message 3 of 4
Flag Post
HP Recommended

Thank you! I was trying to use the solve app which was causing the problem, but using that command in the CAS environment works great, and is probably faster.

Tim_Wessman
Level 8
Level 8
747 744 121 187
Message 4 of 4
Flag Post
HP Recommended

The reason why the solving is not working for you is because it is using a "numerical" method in the solve app. Numerical methods you can think of as a very fast, "guess and check" that will converge to a number that is "close enough". If your initial guesses are too far off - especially in misbehaved or very large changing functions - they do not converge unless close. Your functions are very steep and do not behave nicely in this instance with your initial guesses.

 

Put some intial guesses in the solve app closer to your result, and it WILL jump to them like you expect.

TW

Although I work for the HP calculator group as a head developer of the HP Prime, the views and opinions I post here are my own.
0 Kudos
† The opinions expressed above are the personal opinions of the authors, not of HP. By using this site, you accept the Terms of Use and Rules of Participation