已知无穷数列1x2,2x3,3x4…,n(n+1),… 求:
已知无穷数列1x2,2x3,3x4…,n(n+1),… 求:
求使1x2+2x3+3x4+…+n(n+1)
求数列1/1x2,1/2x3,1/3x4,1/4x5.的前n项和---
数学题目,求速度1x2十2x3+…+100x101=1x2+2x3+…+n(n十1) 1x2x3+2+3x4+…+n(n
数学数列累加求和已知n!=1X2X3X4X.Xn,求1X1!+2X2!+3X3!+4X4!+.+nXn!=?
已知数列1/1x2,1/2x3,1/3x4…1/n(n+1)…,计算S1,S2,S3,由此推测计算Sn的公式,并给出证明
1x2+2x3+3x4+...+n(n+1)=?
一道简便计算数学题1X2+2X3+3X4+4X5...+n(n+1)一1X2+2X3+3X4+4X5...+2013X2
1/1x2+1/2x3+1/3x4+...+1/n(n+1)怎么算
已知函数f(n)=2n/n+2,X1=1,Xn=f(Xn-1).则X2,X3,X4的值分别为多少?...
1 总体X~N(2,4),X1,X2,X3,X4为样本,则(X1+X2+X3+X4)/4~( )
求线性方程组 x2-x3-x4=0 x1+x2-x3+3x4=1 x1-x2+x3+5x4=-1 x1+2x2-2x3+