1/2x2+1/2x3+1/3x4+.+1/99x100+1/n(n+1) 等于多少
1分之1x2+1分之2x3+1分之3x4.+1分之99x100
计算1x2+2x3+3x4+4x5+...+99x100
1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101
1/1x2+1/2x3+1/3x4+1/4x5+.+1/98x99+1/99x100
1/1X2+1/2x3+1/3x4+1/4x5+.+1/98x99+1/99x100求结果!
一定要帮我啊!(1/1x2)+(1/2x3)+(1/3x4)+(1/4x5)+.+(1/99x100)=?
2/1x2+2/2x3+2/3x4+2/4x5+...+2/98x99+2/99x100
求1x2,2x3,3x4,4x5,……98x99,99x100的倒数和
1X2+2X4+3X6+.50X100
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
求使1x2+2x3+3x4+…+n(n+1)