This is documentation for Mathematica 3, which was
based on an earlier version of the Wolfram Language.
View current documentation (Version 11.2)
 Documentation / Mathematica / Built-in Functions / Programming / Tests  /

  • Positive[ x ] gives True if x is a positive number.
  • Positive[ x ] gives False if x is manifestly a negative numerical quantity, a complex numerical quantity, or zero. Otherwise, it remains unevaluated.
  • A definition like Positive[ x ] = True effectively specifies that x is a positive number.
  • Definitions for Sign are tested in determining whether linear combinations of expressions are positive.
  • See also: Negative, NonNegative, Sign.

    Further Examples

    Positive is unsure about -x so doesn't evaluate it further.