Rule of Signs

Author

Eric W. Weisstein
June 30, 2004

This notebook downloaded from http://mathworld.wolfram.com/notebooks/Arithmetic/RuleofSigns.nb.

For more information, see Eric's MathWorld entry http://mathworld.wolfram.com/RuleofSigns.html.

©2005 Wolfram Research, Inc. except for portions noted otherwise

Statement

FullSimplify[Sign[x y],x>0&&y>0]

FullSimplify[Sign[x y],x<0&&y<0]

Refine[Sign[x y],x>0&&y>0]

Refine[Sign[x y],x<0&&y<0]