# Arithmetic Sequence Formulas

## Arithmetic Sequence Formulas:

A sequence is said to be an arithmetic sequence if the difference between the consecutive terms is always constant. This constant is called the common difference denoted by ‘d’ and is given as-

Arithmetic Sequence is also called Arithmetic Progression.

General Form of Arithmetic Sequence:

If ‘a’ be the first term and ‘d’ be the common difference of the arithmetic sequence then the general form of the arithmetic sequence is a, a + d, a + 2d, a + 3d, and so on.

nth– term of Arithmetic Sequence:

If ‘a’ be the first term and ‘d’ be the common difference of an arithmetic sequence, then its nth term is given by-

mth term from the end:

If there are n terms in a sequence, then the mth term from the end is equal to (n – m + 1)th from the beginning.

Selection of terms in Arithmetic Sequence:

If we have to select a certain number of terms in an arithmetic sequence, it is better to select the terms in the following ways-

Sum n-terms of Arithmetic Sequence:

Let Sn be the sum of n terms of an arithmetic sequence, then-

If a be the first term and an be the last term, then-