Isn't possible (may be not in Maple) to declare explicitly the context of interpretation of the symbols, their operations and domains, so that I can get, by a "standard analysis" choice of context,  Alec's f = 1/x - 1/x, "being undefined at 0 and equal 0 otherwise" and Axel, with another choice  get f represent 0?

Isn't there ISO standards for the software development process?

And what about a Maple V Release 5 interface, say, with the earliest kernel/library that works in current OSs?

In fact, that interface works for me better than Classic GUI (not to say Standard...).

adding 'assuming real' to each one is fine. But perhaps for longer calculations it would be more convenient to have a command 'assume(real)' .

adding 'assuming real' to each one is fine. But perhaps for longer calculations it would be more convenient to have a command 'assume(real)' .

There is some FAQ here at MaplePrimes. And relevant, though not FAQ The Top Ten Maple Errors.

But a real FAQ is rather a project  (may be as part of a wiki).

Yes, the result of 'solve', ie the data structure that it generates, is a set of equations.
 

There is some FAQ here at MaplePrimes. And relevant, though not FAQ The Top Ten Maple Errors.

But a real FAQ is rather a project  (may be as part of a wiki).

Yes, the result of 'solve', ie the data structure that it generates, is a set of equations.
 

that produces that error message.

that produces that error message.

subs(s,a);
                             20.30000000

subs(s,a);
                             20.30000000

You can do:

f := x -> (a*b)/sqrt((a*cos(x))^2 + (b*sin(x))^2);
f(0):
eq1:=14.88=simplify(%) assuming  a > 0, b > 0;

                           eq1 := 14.88 = b

f(Pi/2):
eq2 := 20.3 =simplify(%) assuming a > 0, b > 0;              

                           eq2 := 20.3 = a

s:=solve({eq1, eq2}, {a, b});

               s := {a = 20.30000000, b = 14.88000000}

plot(subs(s, eval(f)), 0..2*Pi, coords = polar);

You can do:

f := x -> (a*b)/sqrt((a*cos(x))^2 + (b*sin(x))^2);
f(0):
eq1:=14.88=simplify(%) assuming  a > 0, b > 0;

                           eq1 := 14.88 = b

f(Pi/2):
eq2 := 20.3 =simplify(%) assuming a > 0, b > 0;              

                           eq2 := 20.3 = a

s:=solve({eq1, eq2}, {a, b});

               s := {a = 20.30000000, b = 14.88000000}

plot(subs(s, eval(f)), 0..2*Pi, coords = polar);

has already been reported.

You have not told yet which is your plot.

has already been reported.

You have not told yet which is your plot.