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SEQ002 · Sequences & series · Classes 10–12

Sequences and Series

An arithmetic progression adds the same difference each time.

📐 Formula

aₙ = a + (n − 1)d; Sₙ = n/2 [2a + (n − 1)d]

✏️ Worked example

a = 2, d = 3, n = 5: 2, 5, 8, 11, 14; S₅ = 40.

🌍 Where it is used

Savings plans, seating rows and EMIs.

❓ Quick check

10th term of 3, 7, 11, …: