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Collect
Collect[
expr
,
x
] collects together terms involving the same powers of objects matching x.
Collect[
expr
,
,
, ... 
] collects together terms that involve the same powers of objects matching  ,  , ... .
Collect[
expr
,
var
,
h
] applies h to the expression that forms the coefficient of each term obtained.
Collect[
expr
,
x
] effectively writes expr as a polynomial in x or a fractional power of x.
Examples: Collect[x + n x + m, x] ; Collect[(1+x+y)^3, x].
Collect[
expr
,
x
,
Simplify] can be used to simplify each coefficient separately.
See the Mathematica book: Section 1.4.5, Section 3.3.1.
See also: Series, CoefficientList, Together, Cases.
Further Examples
These two inputs collect terms first in the variable x and then in the variable y.
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This first collects with respect to x, then collects coefficients with respect to y inside of each of the x coefficients.
In[3]:= 
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In this example we use Collect to rewrite an expression by pulling out factors common only to certain parts.
In[4]:= 
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This example has the usual two arguments.
In[5]:= 
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Collect applies an optional third argument to the innermost coefficients of the collected terms.
In[6]:= 
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Suppose you want to collect all the products of powers of x and y in a polynomial that involves other variables. One way is to use patterns.
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Another way is to use MonomialList.
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THIS IS DOCUMENTATION FOR AN OBSOLETE PRODUCT. SEE THE DOCUMENTATION CENTER FOR THE LATEST INFORMATION. | | | |
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