# Question:PDEs boundaries

## Question:PDEs boundaries

Maple

Hi, I'm trying to solve 1-D thermal equation defined below, but I end up with an error : Error, (in pdsolve/numeric/process_PDEs) PDEs can only contain dependent variables with direct dependence on the independent variables of the problem, got {f(t, 1)}.

Could you please point out what am I doing wrong? Perhaps it's how I define the PDe or how I write the boundaries? Any help appreciated!

with(PDEtools)

PDE := cp*diff(T(t, r), t) - k_1*diff(diff(T(t, r), r), r) - k_1*diff(T(t, r), r)/r = Q;

all variables for now have dummy values of 1

cp := 1;
k_2 := 1;
A := 1;
k_3 := 1;
k_4 := 1;
k_5 := 1;
k_6 := 1;
T_amb := 1;

bcs_1 := eval(diff(T(t, r), r), r = 1) = k_3*T_amb;

bcs_2 := eval(diff(T(t, r), r), r = 0) = 0;

bcs_3 := eval(diff(T(t, r), t), t = 0) = 25;

PDE_all := {PDE, bcs_1, bcs_2, bcs_3};

sol := pdsolve(PDE_all, numeric);
Error, (in pdsolve/numeric/process_PDEs) PDEs can only contain dependent variables with direct dependence on the independent variables of the problem, got {f(t, 1)}

﻿