x + y + z represents a sum of terms.

Horizontal Lines opens a submenu to insert a line of the specified thickness above or below the selected cell.

ReplaceList[expr, rules] attempts to transform the entire expression expr by applying a rule or list of rules in all possible ways, and returns a list of the results ...

Most mathematical functions in Mathematica are set up to apply themselves separately to each element in a list. This is true in particular of all functions that carry the ...

Conjunction[expr, {a_1, a_2, ...}] gives the conjunction of expr over all choices of the Boolean variables a_i.

Some basic matrix operations. Transposing a matrix interchanges the rows and columns in the matrix. If you transpose an m×n matrix, you get an n×m matrix as the result. ...

You can give Solve a list of simultaneous equations to solve. Solve can find explicit solutions for a large class of simultaneous polynomial equations. Here is a simple ...

Functions for constructing matrices. This generates a 2×2 matrix whose i,j^th entry is a[i,j]. Here is another way to produce the same matrix.

DialogSymbols is an option for Dialog which gives a list of symbols whose values should be localized in the dialog.

NonConstants is an option for D which gives a list of objects to be taken to depend implicitly on the differentiation variables.