# Question:why Maple hangs on this basic PDE?

## Question:why Maple hangs on this basic PDE?

Maple 2019

I was wondering why Maple hangs on this first order heat pde (waited for more than 15 minutes)

```pde:= diff(u(x,t),t)= diff(u(x, t), x\$2) - 9*diff(u(x,t),x);
bc:=u(0,t)=0,u(1,t)=0;
ic:=u(x, 0) = exp(45/10*x)*(5*sin(Pi*x) + 9*sin(2*Pi*x) + 2*sin(3*Pi*x));
#infolevel[pdsolve]:=3;
pdsolve([pde,ic,bc],u(x,t))
```

It shows it hangs here:

```Trying HINT = _F1(x)*_F2(t)
Trying given functional HINT ...
Third set of solution methods successful
```

Mathematica solves this very quickly and returns

```heqn = D[u[x, t], t] == D[u[x, t], {x, 2}] - 9*D[u[x, t], x];
ic = u[x, 0] == Exp[45/10 x]*(5 Sin[Pi*x] + 9 Sin[2*Pi*x] + 2 Sin[3*Pi*x]);
bc = {u[0, t] == 0, u[1, t] == 0};
sol = DSolve[{heqn, ic, bc}, u[x, t], {x, t}]```

I am asking becuase Maple normally have no problem with such PDE's so I was surprised it hangs on this one and was trying to find out why.

Other than using infolevel[pdsolve]:= what other tools should one try to debug where exactly it hangs and why?

Maple 2019, Physics V 350

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