1⼀1×2+2⼀1×2×3+3⼀1×2×3×4+……8⼀1×2×3×……×9 等于多少?

请告诉我详细过程,谢谢!
2024-12-20 03:38:16
推荐回答(1个)
回答1:

=(1/2+1/3+~~)
=5/6+3/1*2*3*4+4/~~
=23/24+4/~~
=362879/362880