1,2,3的最小公倍数是多?
发布网友
发布时间:2024-05-15 12:47
我来回答
共1个回答
热心网友
时间:2024-07-03 11:39
1,=(1/2)×(1/1×2+1/2×3)+(1/2)×(1/2×3-1/3×4)+……+(1/2)×(1/48×49-1/49×50)
=(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 2,=1/3*(1/2—-1/5)+——+1/3*(1/1994-1/1997) =1/3*(1/2-1/5+1/5-1/8——-+1/1991-1/1994+1/1994-1/1997) =1/3*(1/2-1/1997) =665/3994