This is documentation for Mathematica 7, which was
based on an earlier version of the Wolfram Language.
 Built-in Mathematica Symbol

# Default

 Default[f]gives the default value for arguments of the function f obtained with a _. pattern object. Default[f, i]gives the default value to use when _. appears as the argument of f. Default[f, i, n]gives the default value for the argument out of a total of n arguments. Default[f, ...]=val defines default values for arguments of f.
• _. represents an optional argument to a function, with a default value specified by Default.
• The necessary values for Default[f] must always be defined before _. is used as an argument of f.
• Values defined for Default[f] are stored in DefaultValues[f].
Define 0 to be the default argument for a function f:
_. represents an argument that can be omitted:
If the second argument is omitted, the default value of 0 is used instead:
If both arguments are omitted, both are taken to have the default value 0:
Define 0 to be the default argument for a function f:
 Out[1]=
_. represents an argument that can be omitted:
 Out[2]=
If the second argument is omitted, the default value of 0 is used instead:
 Out[3]=
If both arguments are omitted, both are taken to have the default value 0:
 Out[4]=
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