PRODUCTS
Mathematica
Mathematica Home Edition
Mathematica for Students
Mathematica for the Classroom
grid
Mathematica
Wolfram Lightweight Grid Manager
web
Mathematica
Mathematica Player
(free download)
Mathematica Player Pro
Wolfram
Workbench
Mathematica
Applications
SOLUTIONS
Engineering
Aerospace Engineering & Defense
Chemical Engineering
Electrical Engineering
Image Processing
Industrial Engineering
Materials Science
Mechanical Engineering
Operations Research
Optics
Petroleum Engineering
Biotechnology & Medicine
Bioinformatics
Medical Imaging
Finance, Statistics, & Business Analysis
Actuarial Sciences
Data Analysis & Mining
Econometrics
Economics
Financial Engineering & Mathematics
Financial Risk Management
Statistics
Software Engineering & Content Delivery
Authoring & Publishing
Interface Development
Software Engineering
Web Development
Science
Astronomy
Biological Sciences
Chemistry
Environmental Sciences
Geosciences
Social & Behavioral Sciences
Design, Arts, & Entertainment
Game Design, Special Effects, & Generative Art
Education
Higher Education
Precollege Education
Students
Technology
Interactive Deployment
High-Performance & Parallel Computing (HPC)
See Also: Technology Guide
PURCHASE
Online Store
Other Ways to Buy
Volume & Site Licensing
Contact Sales
Software
Service
Upgrades
Training
Books
FOR USERS
All User Resources
Product Registration
Technical Support
Customer Service
Developer Support
Does My Site Have a License?
Free Seminars
Learning Center
Training
Custom Group Seminars
Documentation & Examples
Tutorial Screencasts
Video Gallery
Demonstrations Project
Education Portal
Student Resources
COMPANY
About Wolfram Research
News & Events
Wolfram Blog
Employment Opportunities
History of
Mathematica
Stephen Wolfram's Home Page
Contact Us
OUR SITES
Wolfram|Alpha
Demonstrations Project
Wolfram Blog
MathWorld
Integrator
Wolfram Functions Site
Mathematica Journal
Wolfram Library Archive
Wolfram
Tones
Wolfram Science
Stephen Wolfram
DOCUMENTATION CENTER SEARCH
Mathematica
>
Mathematics and Algorithms
>
Formula Manipulation
>
Algebraic Transformations
>
Rational Functions
>
Built-in
Mathematica
Symbol
Picking Out Pieces of Algebraic Expressions
Tutorials »
|
Numerator
ExpandDenominator
Rationals
Rational
See Also »
|
Formula Manipulation
Rational Functions
More About »
Denominator
Denominator
[
expr
]
gives the denominator of
expr
.
MORE INFORMATION
Denominator
picks out terms which have superficially negative exponents.
Numerator
picks out all 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 denominators.
Denominator
can be used on rational numbers.
EXAMPLES
CLOSE ALL
Basic Examples
(1)
Extract denominator of a rational number:
In[1]:=
Out[1]=
Extract denominator of a rational expression:
In[2]:=
Out[2]=
Scope
(6)
Options
(2)
Properties & Relations
(5)
Neat Examples
(2)
SEE ALSO
Numerator
ExpandDenominator
Rationals
Rational
TUTORIALS
Picking Out Pieces of Algebraic Expressions
MORE ABOUT
Formula Manipulation
Rational Functions
New in 1
EXAMPLES
Basic Examples 
Scope 