Calculatrice de Suite Arithmétique — Formule

Arithmetic Sequence

nth Term

aₙ = a₁ + (n - 1) × d

Sum of n Terms

Sₙ = n/2 × (2a₁ + (n-1)d)

or equivalently: Sₙ = n/2 × (a₁ + aₙ)

An arithmetic sequence has a constant difference between consecutive terms.

Exemple Résolu

Arithmetic sequence: first term = 3, common difference = 5, find the 10th term and sum.

  1. a₁₀ = 3 + (10-1) × 5 = 3 + 45 = 48
  2. Sum = 10/2 × (3 + 48) = 5 × 51 = 255