Arithmetic

Checks if a progression is arithmetic or not. An arithmetic series is the sum of a sequence in which each term is computed from the previous one by adding (or subtracting) a constant d:

a subscript k equals a subscript k minus 1 end subscript plus d equals... equals a subscript 1 plus d left parenthesis k minus 1 right parenthesis

arithmetic?(Progression)

Given a progression, returns a list. If the progression is not arithmetic, the list just contains an element: false. Else, the list has two elements: true and the value d, following the notation above.

arithmetic?(Expression, Identifier)

Given the expression of the general term and the variable, returns a list. If the progression given by the expression is not arithmetic, the list just contains an element: false. Else, the list has two elements: true and the value d, following the notation above.