100X100—99X99+98X98+...+2X2—1X1

来源：学生作业帮助网 编辑：作业帮 时间：2024/05/02 18:21:18
100X100—99X99+98X98+...+2X2—1X1

100X100—99X99+98X98+...+2X2—1X1
100X100—99X99+98X98+...+2X2—1X1

100X100—99X99+98X98+...+2X2—1X1
100×100-99×99+98×98+...+2×2－1×1
=(100+99)(100-99)+(98+97)(98-97)+...+(2+1)(2-1)
=(100+99)+(98+97)+...+(2+1)
=5050

我知道1+.....100是多少，就是首相+尾相（即1与100）×项数(即100）÷2就是5050，估计还没到你那种算式的程度，到时候我问问我们奥数老师，看看她知不知道。

100X100—99X99+98X98+...+2X2—1X1 100X100—99X99+98X98+...+2X2—1X1等于多少 100X100一99X99+98X98一97X97+,十2X2一1X1 100X100-99X99-98X98-97X97+…+2X2-1X1=? 计算100X100-99X99+98X98-97X97+...+2X2-1X1= 1X1+2X2+3X3+4X4+5X5.+98X98+99X99+100X100=? 100x100-99x99+98x98-97x97+.+4x4-x4-3x3+2x2-1计算 0.25x0.25x...x0.25x4x...x4=1x2分之1+2x3分之1+3x4分之1+4x5分之1+...+97x98分之1+98x99分之1+99x100分之1=(1+2分之1）x（1+3分之1）x（1+4分之1）x...(1+18分之1）x（1+19分之1）x（1+20分之1）= 2x4/1+4x6/1+6x8/1.+96x98/1+98x100/1= 1/1X2+1/2x3+1/3x4+1/4x5+.+1/98x99+1/99x100求结果! 求1x2,2x3,3x4,4x5,……98x99,99x100的倒数和如题 1/1x2+1/2x3+1/3x4+……+1/98x99+1/99x100=…… 2/1x2+2/2x3+2/3x4+2/4x5+...+2/98x99+2/99x100 1x2+2x3+3x4+4x5+······98x99+99x100=? 1/1x2+1/2x3+1/3x4+.1/98x99+1/99x100=?要注明运算过程 1/1x2+1/2x3+1/3x4.1/98x99+1/99x100怎么解 1x2/1+2x3/1+3x4/1+……+98x99/1+99x100/1=? 1x1-2x2+3x3-4x4******+99x99-100x100+101x101的过程教教我