This formula just follows the definition of the arithmetic sequence.Įxample: Find a 21 of an arithmetic sequence if a 19 = -72 and d = 7. There is another formula to find the n th term which is called the ' recursive formula of an arithmetic sequence' and is used to find a term (a n) of the sequence when its previous term (a n-1) and 'd' are known. The above formula for finding the n t h term of an arithmetic sequence is used to find any term of the sequence when the values of 'a 1' and 'd' are known. The following table shows some arithmetic sequences along with the first term, the common difference, and the n th term. This directly follows from the understanding that the arithmetic sequence a 1, a 2, a 3. This is also known as the general term of the arithmetic sequence. The n th term of an arithmetic sequence a 1, a 2, a 3. = 3, 6, 9, 12,15.Ī few more examples of an arithmetic sequence are: Let us verify this pattern for the above example.Ī, a + d, a + 2d, a + 3d, a + 4d. Thus, an arithmetic sequence can be written as a, a + d, a + 2d, a + 3d. is an arithmetic sequence because every term is obtained by adding a constant number (3) to its previous term. The following is an arithmetic sequence as every term is obtained by adding a fixed number 4 to its previous term.Ĭonsider the sequence 3, 6, 9, 12, 15.

It is a 'sequence where the differences between every two successive terms are the same' (or) In an arithmetic sequence, 'every term is obtained by adding a fixed number (positive or negative or zero) to its previous term'. 1.ĭifference Between Arithmetic Sequence and Geometric SequenceĪn arithmetic sequence is defined in two ways. Let us learn the definition of an arithmetic sequence and arithmetic sequence formulas along with derivations and a lot more examples for a better understanding.

$arithmetic sequence formula sum$

If we want to find any term in the arithmetic sequence then we can use the arithmetic sequence formula. The formula to find the sum of first n terms of an arithmetic sequence.The formula for finding n th term of an arithmetic sequence.We have two arithmetic sequence formulas. For example, the sequence 1, 6, 11, 16, … is an arithmetic sequence because there is a pattern where each number is obtained by adding 5 to its previous term. A sequence is a collection of numbers that follow a pattern. The arithmetic sequence is the sequence where the common difference remains constant between any two successive terms.

Arithmetic sequence formula sum