Application Guide

68 Alphabetical Listing
F
factor()
Catalog >
factor(Expr1[, Var]) ⇒ expression
factor(List1[,Var]) ⇒ list
factor(Matrix1[,Var]) ⇒ matrix
factor(Expr1) returns Expr1 factored with
respect to all of its variables over a
common denominator.
Expr1 is factored as much as possible
toward linear rational factors without
introducing new non-real subexpressions.
This alternative is appropriate if you want
factorization with respect to more than one
variable.
factor(Expr1,Var) returns Expr1 factored
with respect to variable Var.
Expr1 is factored as much as possible
toward real factors that are linear in Var,
even if it introduces irrational constants or
subexpressions that are irrational in other
variables.
The factors and their terms are sorted with
Var as the main variable. Similar powers of
Var are collected in each factor. Include
Var if factorization is needed with respect
to only that variable and you are willing to
accept irrational expressions in any other
variables to increase factorization with
respect to Var. There might be some
incidental factoring with respect to other
variables.
For the Auto setting of the Auto or
Approximate mode, including Var permits
approximation with floating-point
coefficients where irrational coefficients
cannot be explicitly expressed concisely in
terms of the built-in functions. Even when
there is only one variable, including Var
might yield more complete factorization.
Note: See also comDenom() for a fast way
to achieve partial factoring when factor() is
not fast enough or if it exhausts memory.