1×2×3分之1+2×3×4分之1加3×4×5分之1+.......+48×49×50分之1

2024-11-23 09:14:00
推荐回答(1个)
回答1:

=1/2×(1/1×2-1/2×3+1/2×3-1/3×4+……+1/48×49-1/49×50)
=1/2×(1/1×2-1/49×50)
=306/1225