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

# NumericFunction

 NumericFunctionis an attribute that can be assigned to a symbol f to indicate that should be considered a numeric quantity whenever all the are numeric quantities.
• Most standard built-in mathematical functions have the attribute NumericFunction.
• If you assign the attribute NumericFunction to a function that does not yield numerical values, then NumericQ will give misleading results.
Exp has the NumericFunction attribute:
When Exp has an argument that is a number, constant, or numeric, the result is numeric:
In most cases when NumericQ[expr] gives True, then N[expr] yields an explicit number:
Exp has the NumericFunction attribute:
 Out[1]=
When Exp has an argument that is a number, constant, or numeric, the result is numeric:
 Out[2]=
In most cases when NumericQ[expr] gives True, then N[expr] yields an explicit number:
 Out[3]=
 Scope   (2)
Define to be a numeric function:
If you have not assigned to yield numerical values, then NumericQ gives misleading results:
Assign to evaluate for arguments that are approximate numbers:
The system symbols that are numeric functions:
 Applications   (1)
Define a function that can represent an exact value:
Assign N to give the derivative with respect to a of the solution of an ODE at :
Assign f for approximate numbers:
f[1] does not evaluate but represents a number:
It will work with any precision (within reasonable limits!):
A plot of the function:
New in 3