Question

Calcular la suma de: S = 2 + 6 + 12 + 20 + ……. + 870

Answer 1

Explicación paso a paso:

1×2+2×3+3×4+4×5+5×6+........+n(n+1)

n(n+1)=870

n=29

La fórmula es

n(n+1)(n+2)/3

Reemplazamos

29(30)(31)/3 = 8990