lhs =. removes any rules defined for lhs.

AlgebraicNumberDenominator[a] gives the smallest positive integer n such that n a is an algebraic integer.

SpheroidalS2Prime[n, m, \[Gamma], z] gives the derivative with respect to z of the radial spheroidal function S_n^m, (2)(\[Gamma], z) of the second kind.

The functionality of NumericalMath`ListIntegrate` is now accessible by using the built-in Mathematica kernel functions Integrate and Interpolation.

BitShiftRight[n, k] shifts the binary bits in the integer n to the right by k places, dropping bits that are shifted past the unit's position on the right. BitShiftRight[n] ...

Compress[expr] gives a compressed representation of expr as a string.

Drop[list, n] gives list with its first n elements dropped. Drop[list, -n] gives list with its last n elements dropped. Drop[list, {n}] gives list with its n\[Null]^th ...

InString[n] is a global object that is assigned to be the text of the n\[Null]^th input line.

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).

UnitVector[k] gives the two-dimensional unit vector in the k\[Null]^th direction.UnitVector[n, k] gives the n-dimensional unit vector in the k\[Null]^th direction.