IntegerPart[x] gives the integer part of x.

LinearSolve[m, b] finds an x which solves the matrix equation m.x == b. LinearSolve[m] generates a LinearSolveFunction[...] which can be applied repeatedly to different b.

ListInterpolation[array] constructs an InterpolatingFunction object that represents an approximate function that interpolates the array of values given. ...

Pochhammer[a, n] gives the Pochhammer symbol (a) n.

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.

Around 1870, Marius Sophus Lie realized that many of the methods for solving differential equations could be unified using group theory. Lie symmetry methods are central to ...

NDSolve returns solutions as InterpolatingFunction objects. Most of the time, simply using these as functions does what is needed, but occasionally it is useful to access the ...

Many calculations involve solving systems of linear equations. In many cases, you will find it convenient to write down the equations explicitly, and then solve them using ...

Mathematica has many powerful features which enable you to solve many kinds of equations.

HarmonicNumber[n] gives the n\[Null]^th harmonic number H_n. HarmonicNumber[n, r] gives the harmonic number H_n^(r) of order r.