InverseSeries[s] takes the series s, and gives a series for the inverse of the function represented by s. InverseSeries[s, x] uses the variable x in the inverse series.

DisplayForm[expr] prints with low-level boxes inside expr shown in explicit two-dimensional or other form.

"Values for Symbols" discussed how you can use transformation rules of the form x->value to replace symbols by values. The notion of transformation rules in Mathematica is, ...

InverseFourierCosTransform[expr, \[Omega], t] gives the symbolic inverse Fourier cosine transform of expr. InverseFourierCosTransform[expr, {\[Omega]_1, \[Omega]_2, \ ...}, ...

InverseFourierSinTransform[expr, \[Omega], t] gives the symbolic inverse Fourier sine transform of expr. InverseFourierSinTransform[expr, {\[Omega]_1, \[Omega]_2, \ ...}, ...

NumberPoint is an option for NumberForm and related functions which gives the string to use as a decimal point.

"s_1" <> "s_2" <> ..., StringJoin["s_1", "s_2", ...], or StringJoin[{"s_1", "s_2", ...}] yields a string consisting of a concatenation of the s_i.

Here is the integral ∫x^n dx in Mathematica. Here is a slightly more complicated example. Mathematica knows how to do almost any integral that can be done in terms of ...

Catch[expr] returns the argument of the first Throw generated in the evaluation of expr. Catch[expr, form] returns value from the first Throw[value, tag] for which form ...

Tally[list] tallies the elements in list, listing all distinct elements together with their multiplicities.Tally[list, test] uses test to determine whether pairs of elements ...