Fw: Non-polinomial equations



On Sun, Jan 09, 2005 at 06:51:08PM +0100, Cosimo Fornaro wrote:
> 
> I'd like to know if maxima can solve equations with absolute values or irrational equations.
> I tried the followings:
> 
> 1) solve(abs(x)=2,x);

If x is complex, abs(x) stands for its modulus and the equation has
an infinite number of solutions. If x is real, Maxima will find each of the
two solutions if you use "assume":

(C2) assume(x>0);

(D2)                                [x > 0]
(C3) solve(abs(x)=2,x);

(D3)                                [x = 2]
(C4) forget(x>0);

(D4)                                [x > 0]
(C5) assume(x<0);

(D5)                                [x < 0]
(C6) solve(abs(x)=2,x);

(D6)                               [x = - 2]

I don't know whether there is a way of defining x as real, or whether
solve would return the two solutions if it knew x was real.

Cheers,
Jaime