SIGN _ _ _ _ _ _ _ _ _ _ _ _ operator

syntax:

signtries to evaluate the sign of its argument. If this is possible sign returns one of 1, 0 or -1. Otherwise, the result is the original form or a simplified variant.

examples:

        sign(-5) 

  -1


        sign(-a^2*b) 

  -SIGN(B)

Even powers of formal expressions are assumed to be positive only as long as the switch complex is off.