I have the following code:

restart;

PDE := diff(u(x, t), t) = diff(u(x, t), x, x)-sin(x+t)+cos(x+t);

IBC:= D[1](u)(0,t)=-sin(t),

D[1](u)(1,t)=-(u(1, t))^4+(cos(1+t))^4-sin(1+t),

u(x,0)=cos(x);

pds := pdsolve( PDE, [IBC], numeric, time = t, range = 0 .. 1,

spacestep = 0.1e-1, timestep = 0.1e-1,

errorest=true

)

And I want to plot the difference |pds(t,x) - cos(x+t)| in maple for x=1 and t=0..5

I thought to use the following piece of commands but I get an error:

P:=unapply(pds, t,x);

Q:=abs(P(t,x)-cos(x+t));

Q:-plot(x=1, t=0..1);

I get an error that Q isn't a module.

I thought that unapply is used for this case, can you help me with this simple task?

Thanks in advance.