FactorTerms[poly] pulls out any overall numerical factor in poly. FactorTerms[poly, x] pulls out any overall factor in poly that does not depend on x. FactorTerms[poly, {x_1, ...
Fibonacci[n] gives the Fibonacci number F_n. Fibonacci[n, x] gives the Fibonacci polynomial F_n (x).
The functions FindMinimum, FindMaximum, and FindRoot have the HoldAll attribute and so have special semantics for evaluation of their arguments. First, the variables are ...
TrigExpand[expr] expands out trigonometric functions in expr.
ContextToFileName["context"] gives the string specifying the file name that is by convention associated with a particular context.
NumberPoint is an option for NumberForm and related functions which gives the string to use as a decimal point.
StackInhibit[expr] evaluates expr without modifying the evaluation stack.
$Aborted is a special symbol that is returned as the result from a calculation that has been aborted.
$LicenseID is a string that gives the license ID under which Mathematica is being run.
$Notebooks is True if Mathematica is being used with a notebook-based front end.