FourierSeries[expr, t, n] gives the n\[Null]^th-order Fourier series expansion of expr in t. FourierSeries[expr, {t_1, t_2, ...}, {n_1, n_2, ...}] gives the multidimensional ...
FourierSinCoefficient[expr, t, n] gives the n\[Null]^th coefficient in the Fourier sine series expansion of expr.FourierSinCoefficient[expr, {t_1, t_2, ...}, {n_1, n_2, ...}] ...
FourierSinSeries[expr, t, n] gives the n\[Null]^th-order Fourier sine series expansion of expr in t.FourierSinSeries[expr, {t_1, t_2, ...}, {n_1, n_2, ...}] gives the ...
FourierTransform[expr, t, \[Omega]] gives the symbolic Fourier transform of expr. FourierTransform[expr, {t_1, t_2, ...}, {\[Omega]_1, \[Omega]_2, ...}] gives the ...
FourierTrigSeries[expr, t, n] gives the n\[Null]^th-order Fourier trigonometric series expansion of expr in t.FourierTrigSeries[expr, {t_1, t_2, ...}, {n_1, n_2, ...}] gives ...
FractionBox[x, y] is a low-level formatting construct that represents x/y in notebook expressions.
FractionBoxOptions -> {opt_1 -> val_1, opt_2 -> val_2, ...} is an option for cells that specifies settings for FractionBox objects within the cell.
FractionLine is an option for fractions that specifies the thickness of the line separating the numerator and denominator.
FrameBox[box] is a low-level box construct which represents box with a frame drawn around it.
Framed
(Built-in Mathematica Symbol) Framed[expr] displays a framed version of expr.