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SeqLab
Sequences and their partial sums.
A sequence is the list of terms itself (2, 5, 8, 11…); a series is what you get when you add those terms together — the running total up to any point is called a partial sum.
Total interest paid over a loan's life, total distance covered by a bouncing ball, or total seats across all rows of a stadium are all partial-sum problems in disguise.
aₙ (nth term)
29
aₙ = a₁ + (n−1)d
What you entered
nth term: a₁ + (n−1)d
2 + (10−1) × 3= 29Sum of first n terms
(10/2) × (2×2 + (10−1)×3)= 155Result
aₙ (nth term): 29
Starting at 2 with common difference 3, term 10 is 29, and the first 10 terms sum to 155.