1/2x3x4+1/3x4x5+1/4x5x6+……+1/48x49x50=x是乘号!过程.答案.

1/2x3x4+1/3x4x5+1/4x5x6+……+1/48x49x50=x是乘号!过程.答案.
1/2x3x4+1/3x4x5+1/4x5x6+……+1/48x49x50=
x是乘号!过程.答案.

1/2x3x4+1/3x4x5+1/4x5x6+……+1/48x49x50=x是乘号!过程.答案.
裂项求和
1/((n-1)n(n+1))=(1/2)*(1/((n-1)n)-1/(n(n+1)))
接着便可算了
结果我算的是(1/2)*(1/6-1/(49*50))