Solve System of differential equations - 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: Solve System of differential equations ( /thread-12076.html) |

Solve System of differential equations - PepePepe - 01-03-2019 09:09 AM
How can I solve a system of differential equations in the HP Prime? Something like this: x1'=x1+2*x2
x2'=3*x1+2*x2 I've tried to use desolve, but it seems it only works for one differential equation. Thanks! RE: Solve System of differential equations - parisse - 01-03-2019 12:44 PM
desolve(y'=[[1,2],[3,2]]*y,t,y) RE: Solve System of differential equations - PepePepe - 01-03-2019 07:39 PM
But it seems that HP Prime it's doing something wrong if I do that. For example: desolve(y'=[[1,0],[0,2]]*y,t,y) gives the same solution as desolve(y'=[[1,0],[0,2]]*y + [[3],[4]] ,t,y) I think it is because the calculator is interpreting [[1,0],[0,2]]*y as [[y,0],[0,2y]] (it doesn't take into account that y is a vector) How could I solve this? Am I doing something wrong? Thanks! RE: Solve System of differential equations - parisse - 01-05-2019 08:47 PM
Correct syntax for second member is s:=desolve(y'=[[1,0],[0,2]]*y + [3,4] ,t,y) The reason is that y is a line vector, not a column vector. Indeed desolve returns a list of generic solutions, even for linear ODE, because you might get several generic solutions for non linear ODE. That mean that the solution y is s[0], i.e. a line vector. |