Question

1×2×3×4+3×4×5×6+5×6×7×8+······﹢97×98×99×100求解

Answer 1

5 * n(n+1)(n+2)(n+3) = n(n+1)(n+2)(n+3)(n+4) - (n-1)n(n+1)(n+2)(n+3)

设A为所求,

则5A = 97*98*99*100*101

A = 97*98*99*50*101