3.1x2x3+2+3x4+…+n(n+1)(n+2)
3.1x2x3+2+3x4+…+n(n+1)(n+2)
求和1x2x3+2x3x4+...+n(n+1)(n+2)
数学题目,求速度1x2十2x3+…+100x101=1x2+2x3+…+n(n十1) 1x2x3+2+3x4+…+n(n
1x2x3+2x3x4+3x4x5+4x5x6+...+n(n+1)(n+2)=
已知无穷数列1x2,2x3,3x4…,n(n+1),… 求:
求使1x2+2x3+3x4+…+n(n+1)
1/(1x2x3)+1/(2x3x4)+1/(3x4x5)+.1/(nx(n+1)x(n+2)=?
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
急,裂项法计算1.1/1x2x3+1/2x3x4+…+1/n(n+1)(n+2)2.2/(X+2)(X+4)+2/(X+
(1/(n^2 n 1 ) 2/(n^2 n 2) 3/(n^2 n 3) ……n/(n^2 n n)) 当N越于无穷大
1/1x2+1/2x3+1/3x4+...+1/n(n+1)怎么算
1x2+2x3+3x4+...+n(n+1)=?