Question

S= 1×2+2×3+3×4+....+24×25

Answer 1

Observación:

• 1x2+2x3 + 3x4+ 4x5 + ....... + n(n+1) = n(n+1)(n+2)/3

Entonces:

Para: S = 1x2+2x3+3x4......+24x25  ,  tendremos que n=24, reemplazando:

S = 24(24+1)(24+2)/3
S = 24(25)(26)/3 = 8*25*26
S = 5200

Eso es todo! Saludos! Jeizon1L