ExpandNumerator

ExpandNumerator[expr]
expands out products and powers that appear in the numerator of expr.

ExpandNumerator automatically threads over lists, as well as equations, inequalities, and logic functions.

Expand the numerator of a fraction:

Out[1]=

Expand the numerator of a rational function:

ExpandNumerator threads over sums:

ExpandNumerator threads over Boolean combinations of equations and inequalities:

Expand the numerator over the integers modulo 3:

Expand the numerator using expansion formulas for trigonometric functions:

ExpandNumerator leaves the denominator unexpanded:

ExpandDenominator expands the denominator, leaving the numerator unexpanded:

Expand expands the numerator and expands the fraction into a sum of fractions:

ExpandAll expands the numerator, the denominator, and the fraction:

Use Factor, Numerator, and Denominator to factor the numerator back: