已知a1=1/1x2x3+1/2=2/3,a2=1/2x3x4+1/3=3/8,a3=1/3x4x5+1/4=4/15,

来源：学生作业帮编辑：作业帮分类：数学作业时间：2024/11/09 00:50:01

已知a1=1/1x2x3+1/2=2/3,a2=1/2x3x4+1/3=3/8,a3=1/3x4x5+1/4=4/15,.依据上述规律,则a99=?
依据上述规律,则a99=?

a99=1/99*100*101+1/100=100/9999

1x2X3+2x3X4+3x4X5+…+7X8X9=? 1x2x3+2x3x4+3x4x5+...+7x8x9=, 1/1x2x3+1/2x3x4+1/3x4x5+1/4x5x6+.+1/48x49x50= 请1/1x2x3+1/2x3x4+1/3x4x5+1/4x5x6= 1x2x3+2x3x4+3x4x5+4x5x6+...+n(n+1)(n+2)= 1/1x2x3+1/2x3x4+1/3x4x5+.+1/11x12x13= 1/1x2x3+1/2x3x4+1/3x4x5+.+1/9x10x11= 1/(1x2x3)+1/(2x3x4)+1/(3x4x5)+.1/(20x21x22)=? 1/1x2x3+1/2x3x4+1/3x4x5+.1/98x99x100= 1x2x3+2x3x4+3x4x5+…+8x9x10 1/1x2x3+1/2x3x4+1/3x4x5+1/4x5x6+1/5x6x7=?这类题 1x2=(1/3)(1x2x3-0x1x2) 3x4=(1/3)(3x4x5-2x3x4) 问1x2x3+2x3x4+.