You have to use the editor in the source mode, and Input format set to "Filtered HTML" .

You have to use the editor in the source mode, and Input format set to "Filtered HTML" .

A pointer to the original forum post might help to elucidate this point.

A pointer to the original forum post might help to elucidate this point.

Using:

SolveTools:-Inequality:-LinearMultivariateSystem(eqs,[d,a,b]) 
assuming integer;

I get the answer in about 5s, parametrized in terms of 'c'.

Using:

SolveTools:-Inequality:-LinearMultivariateSystem(eqs,[d,a,b]) 
assuming integer;

I get the answer in about 5s, parametrized in terms of 'c'.

There is a statement in ?pdsolve,numeric > Time-based Solver:

The solver has two modes of operation.

 - The first mode of operation uses the default method, which is a centered implicit scheme, and is capable of finding solutions for higher order PDE or PDE systems. The PDE systems must be sufficiently close to a standard form for the method to find the numerical solution.

which I find quite enigmatic, as "standard form" is not clearly defined, less "closeness" to this standard form. So, I do not find of much help that error message.

There is a statement in ?pdsolve,numeric > Time-based Solver:

The solver has two modes of operation.

 - The first mode of operation uses the default method, which is a centered implicit scheme, and is capable of finding solutions for higher order PDE or PDE systems. The PDE systems must be sufficiently close to a standard form for the method to find the numerical solution.

which I find quite enigmatic, as "standard form" is not clearly defined, less "closeness" to this standard form. So, I do not find of much help that error message.

In Classic GUI, solid circle is available using plotsetup(maplet):

In Classic GUI, solid circle is available using plotsetup(maplet):

You could post them by the "Submit Maple Software Change Request" form that opens with the link at the left.

You could post them by the "Submit Maple Software Change Request" form that opens with the link at the left.

Phaseplan is one thing. Arrows is another price...

Nothing very suitable seems to be available for this case. But in principle, you could get some arrows tangent to a solution curve using e.g. VectorCalculus:-PlotPositionVector.

Phaseplan is one thing. Arrows is another price...

Nothing very suitable seems to be available for this case. But in principle, you could get some arrows tangent to a solution curve using e.g. VectorCalculus:-PlotPositionVector.

Indeed, such change is required.