Question about to_poly_solve



I changed the source of to_poly_solve.mac so that it internally defaults algexact to true. A user can override the default by appending
'algexact=false to the %solve (or to_poly_solve) argument list.  Notice that algexact : false does not guarantee a float result
(see the user documentation for algexact).


Example

Use default algexact

(%i2) %solve(max(1-x^2,2)=x^3,x);

(%o2) %union([x = 2^(1/3)],[x = (2^(1/3)*sqrt(3)*%i-2^(1/3))/2],
             [x = -(2^(1/3)*sqrt(3)*%i+2^(1/3))/2])

(%i3) float(%);

(%o3) %union([x = 1.259921049894873],
             [x = 0.5*(2.182247271943443*%i-1.259921049894873)],
             [x = -0.5*(2.182247271943443*%i+1.259921049894873)])

Grumble why the need for expand...

(%i4) expand(%);

(%o4) %union([x = 1.259921049894873],
             [x = -1.091123635971721*%i-0.629960524947437],
             [x = 1.091123635971721*%i-0.629960524947437])

Override algexact default:

(%i5) %solve(max(1-x^2,2)=x^3,x,'algexact=false);

(%o5) %union([x = 1.259921095381759],
             [x = -1.091123635971721*%i-0.629960524947437],
             [x = 1.091123635971721*%i-0.629960524947437])

Let me guess that the Sage developers will at least need to change some test results. So it goes.

--Barton