>>>>> "Poul" == Poul Riis writes:
Poul> To be more specific my question is:
Poul> Is there a 'stronger' command than 'solve', or can I set some parameter so
Poul> that maxima actually can solve an equation like
Poul> solve(sqrt((x-a*e)^2+y^2)+sqrt((x+a*e)^2+y^2)=2*a,y);
I am not a very good maxima user, but here is a transcript of a
solution. solve by itself doesn't produce a solution, but with some
more manipulations you can obtain a solution. This assumes e above is
not %e.
(%i1) solve(sqrt((x-a*e)^2+y^2)+sqrt((x+a*e)^2+y^2)=2*a,y);
2 2 2 2 2 2 2 2
(%o1) [sqrt(y + x + 2 a e x + a e ) = 2 a - sqrt(y + x - 2 a e x + a e )]
(%i2) part(%,1)^2;
2 2 2 2 2 2 2 2 2
(%o2) y + x + 2 a e x + a e = (2 a - sqrt(y + x - 2 a e x + a e ))
(%i3) solve(%,y);
Is a - e x positive, negative, or zero?
pos;
2 2 2 2 2 2 2 2 2 2 2 2
(%o3) [y = - sqrt(e x - x - a e + a ), y = sqrt(e x - x - a e + a )]
Ray