Арифметическая и геометрическая прогрессия: n-й элемент и сумма
The progression calculator finds the nth term and the sum of the first n terms of an arithmetic or geometric sequence.
Arithmetic: a_n = a₁ + (n−1)×d, S_n = n/2×(2a₁+(n−1)d). Geometric: a_n = a₁×q^(n−1), S_n = a₁×(q^n−1)/(q−1) for q ≠ 1.
Arithmetic a₁=1, d=2, n=5: a₅=9, S₅=25. Geometric a₁=1, q=2, n=5: a₅=16, S₅=31.
Loading calculator…