Algebra
Basic

Arithmetic nth Term

The nth term of an arithmetic sequence.

Formula

an=a1+(n−1)da_n = a_1 + (n-1)d

Variables

a_1First term
dCommon difference
nTerm index

Example

Sequence 3, 7, 11, … (a₁=3, d=4): the 10th term is a₁₀ = 3 + 9×4 = 39.

Did You Know?

Arithmetic sequences model anything that grows by a fixed step — stadium seating, loan payments, stacking bricks.

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