This is documentation for Mathematica 8, which was
based on an earlier version of the Wolfram Language.
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# Numerator

 Numerator[expr]gives the numerator of expr.
• Numerator picks out terms which do not have superficially negative exponents. Denominator picks out the remaining terms.
• An exponent is "superficially negative" if it has a negative number as a factor.
• The standard representation of rational expressions as products of powers means that you cannot simply use Part to extract numerators.
Extract the numerator of a rational number:
Extract the numerator of a rational expression:
Extract the numerator of a rational number:
 Out[1]=
Extract the numerator of a rational expression:
 Out[2]=
 Scope   (6)
Rational numbers:
Rational expressions:
Select terms without syntactically negative exponents:
All exponents syntactically negative:
No syntactically negative exponents:
Numerator automatically threads over lists:
 Options   (2)
Find numerators over integers modulo :
Numerators of trigonometric functions:
Denominator gives the terms with negative exponents:
An expression is a quotient of its numerator and denominator:
Use Cancel to cancel common factors between the numerator and the denominator:
Together writes an expression as a fraction and cancels common terms:
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