Hello group,
Consider
,----
| (%i21) tlimswitch : false;
| (%o21) false
| (%i22) limit(sqrt(x^2 + x +1) + x, x, minf);
| Is x positive or negative?
|
| pos;
| 1
| (%o22) - -
| 2
| (%i23) limit(sqrt(x^2 + x +1) + x, x, minf);
| Is x positive or negative?
|
| neg;
| (%o23) minf
`----
If we take a limit as x -> -oo, then we should assume that x is
negative and no question should be asked at all. %o22 is the right
answer for the original limit, although in the given context is
wrong or, rather, meaningless. And of course %o23 is wrong.
Best,
Nikos