Solving partial differential equations with the HP Prime and HP 40gs

[carey]

(09-05-2023 10:59 PM)Anthony The Koala Wrote:  (1) I have seen a way to solve a pde for the HP Prime at http://computerlearningservice.com/Acade...Pfunctions

That link shows how to take a partial derivative (not solve a PDE) on the Prime. Despite the word "partial" that they have in common, taking a "partial" derivative is a different (and far simpler) problem than solving a "partial" differential equation with initial and boundary conditions.

(09-05-2023 10:59 PM)Anthony The Koala Wrote:  The documentaion in the HP 40GS manual is lacking in the functions LAP DESOLVE
and ILAP.

As mentioned in my previous post, desolve() is a Prime command, not a 40GS command, and therefore is not found in the 40GS manual. However, LAP and ILAP are found on pages 14-65 through 14-67 of the 40GS manual along with a few ODE examples. Also mentioned in my previous post, these commands "may only solve ODEs and not PDEs" as it appears they work only with 1 independent variable, not 2, and therefore are unlikely to accomplish the PDE to ODE conversion shown in my post.

To put things in perspective, XCAS is the Prime's CAS system (more powerful than its predecessor found in the 40GS), and I find no mention of PDEs in the XCAS Reference manual (partial derivatives yes, PDEs no).

Hence, while the type of numerical solution I also outlined can be programmed on either calculator, it's doubtful that the goal you stated in the following is possible on any handheld calculator with respect to obtaining a closed-form solution to a PDE with initial and boundary conditions (but would love to be proven wrong!).

(09-05-2023 10:59 PM)Anthony The Koala Wrote:  But I want to know what to key in the buttons to solve the problem.