ArcCosh (Built-in Mathematica Symbol)

ArcCosh[z] gives the inverse hyperbolic cosine cosh -1 (z) of the complex number z.

ArcTan (Built-in Mathematica Symbol)

ArcTan[z] gives the arc tangent tan -1 (z) of the complex number z. ArcTan[x, y] gives the arc tangent of y/x, taking into account which quadrant the point (x, y) is in.

ArithmeticGeometricMean (Built-in Mathematica Symbol)

ArithmeticGeometricMean[a, b] gives the arithmetic-geometric mean of a and b.

Ceiling (Built-in Mathematica Symbol)

Ceiling[x] gives the smallest integer greater than or equal to x. Ceiling[x, a] gives the smallest multiple of a greater than or equal to x.

CosIntegral (Built-in Mathematica Symbol)

CosIntegral[z] gives the cosine integral function Ci(z).

Factorial2 (Built-in Mathematica Symbol)

n!! gives the double factorial of n.

LegendreQ (Built-in Mathematica Symbol)

LegendreQ[n, z] gives the Legendre function of the second kind Q_n (z). LegendreQ[n, m, z] gives the associated Legendre function of the second kind Q_n^m(z).

LogIntegral (Built-in Mathematica Symbol)

LogIntegral[z] is the logarithmic integral function li(z).

ModularLambda (Built-in Mathematica Symbol)

ModularLambda[\[Tau]] gives the modular lambda elliptic function \[Lambda](\[Tau]).

RiemannSiegelZ (Built-in Mathematica Symbol)

RiemannSiegelZ[t] gives the Riemann\[Dash]Siegel function Z(t).