@hermitian 

You can also use %^%H assuming x1::real, x2::real, y1::real, y2::real;

@Robert Israel 

Hi all

Thank you for your explanations. I understand what you mean.

"To work, solve use assumptions but not in solving" ?

Best wishes

@Robert Israel 

Hi all

Thank you for your explanations. I understand what you mean.

"To work, solve use assumptions but not in solving" ?

Best wishes

@Preben Alsholm look here

restart:f:=x->x^2+3:
> res:=solve(f(x)=0,x) assuming diff(f(x),x)>0, diff(diff(f(x),x),x)<0;

Error, (in assuming) when calling 'assume'. Received: 'contradictory assumptions'

The assumptions are taken into account

@Preben Alsholm look here

restart:f:=x->x^2+3:
> res:=solve(f(x)=0,x) assuming diff(f(x),x)>0, diff(diff(f(x),x),x)<0;

Error, (in assuming) when calling 'assume'. Received: 'contradictory assumptions'

The assumptions are taken into account

@Preben Alsholm : If there are parameters in the input equations, the solve command will use those assumptions in its computations.".good.

I think, when maple accept assuming, even when the result is the same as without assuming, this property is satisfied in the result ?

solve don't accept assume in solve.

@Robert Israel : solve accept assuming ...

@Preben Alsholm : If there are parameters in the input equations, the solve command will use those assumptions in its computations.".good.

I think, when maple accept assuming, even when the result is the same as without assuming, this property is satisfied in the result ?

solve don't accept assume in solve.

@Robert Israel : solve accept assuming ...

Maple accept:

f:=x->sin(x^3+4);

solve(f(x)=0,x) assuming diff(f(x),x)>0, diff(diff(f(x),x),x)<0;

but not assume, ok

Maple accept:

f:=x->sin(x^3+4);

solve(f(x)=0,x) assuming diff(f(x),x)>0, diff(diff(f(x),x),x)<0;

but not assume, ok

It's ok, thank you

It's ok, thank you

You are right in plots[implicitplot]

You are right in plots[implicitplot]

change also the name of your list as listx for example

change also the name of your list as listx for example