MathieuCharacteristicExponent (Built-in Mathematica Symbol)

MathieuCharacteristicExponent[a, q] gives the characteristic exponent r for Mathieu functions with characteristic value a and parameter q.

RamanujanTauTheta (Built-in Mathematica Symbol)

RamanujanTauTheta[t] gives the Ramanujan tau theta function \[Theta](t).

SphericalBesselJ (Built-in Mathematica Symbol)

SphericalBesselJ[n, z] gives the spherical Bessel function of the first kind j_n (z).

SphericalBesselY (Built-in Mathematica Symbol)

SphericalBesselY[n, z] gives the spherical Bessel function of the second kind y_n (z).

SphericalHankelH2 (Built-in Mathematica Symbol)

SphericalHankelH2[n, z] gives the spherical Hankel function of the second kind h_n^(2)(z).

WeberE (Built-in Mathematica Symbol)

WeberE[\[Nu], z] gives the Weber function E \[Nu] (z).WeberE[\[Nu], \[Mu], z] gives the associated Weber function E_\[Nu]^\[Mu](z).

If (Built-in Mathematica Symbol)

If[condition, t, f] gives t if condition evaluates to True, and f if it evaluates to False. If[condition, t, f, u] gives u if condition evaluates to neither True nor False.

OwenT (Built-in Mathematica Symbol)

OwenT[x, a] gives Owen's T function T(x, a).

Compiling Mathematica Expressions (Mathematica Tutorial)

If you make a definition like f[x_]:=x Sin[x], Mathematica will store the expression x Sin[x] in a form that can be evaluated for any x. Then when you give a particular value ...

SetDelayed (Built-in Mathematica Symbol)

lhs := rhs assigns rhs to be the delayed value of lhs. rhs is maintained in an unevaluated form. When lhs appears, it is replaced by rhs, evaluated afresh each time.