AlgebraArithmetic Progressions

Sum of an AP

Sₙ = n/2 [2a + (n−1)d] — check it against direct addition.

First term2

Common difference4

Number of terms12

Last term

Sum Sₙ

288

Using n/2(a + l)

288

Arithmetic progression — terms growing by dLast term: 46

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Both formulas agree — the second one is handy when the last term is known.

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