1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+1/6x7

来源：学生作业帮编辑：拍题作业网作业帮分类：数学作业时间：2024/04/29 03:06:12

1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+1/6x7
1/2+1/6+1/12+1/20+.+1/420
2/3+2/15+2/35+2/63+2/99+2/143
(1-1/50)X(1-1/49)X(1-1/48)X......X(1-1/4)X(1-1/3)
1/1x3+1/3x5+1/5x7+1/7x9+1/9x11

1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+1/6x7
=（1-1/2）+（1/2-1/3）+（1/3-1/4）+（1/4-1/5）+（1/5-1/6）+（1/6-1/7）
=1-1/7
=6/7
1/2+1/6+1/12+1/20+.+1/420
=（1-1/2）+（1/2-1/3）+（1/3-1/4）+（1/4-1/5）+（1/5-1/6）+（1/6-1/7）+.+（1/20-1/21）
=1-1/21
=20/21
2/3+2/15+2/35+2/63+2/99+2/143
=（1-1/3）+（1/3-1/5）+（1/5-1/7）+（1/7-1/9）+（1/9-1/11）+（1/11-1/13)
=1-1/13
=12/13
(1-1/50)X(1-1/49)X(1-1/48)X.X(1-1/4)X(1-1/3)
=49/50X48/49.X3/4X2/3
=2/50
=1/25
1/1x3+1/3x5+1/5x7+1/7x9+1/9x11
=（1/1x3+1/3x5）+1/5x7+1/7x9+1/9x11
=2/5+1/5x7+1/7x9+1/9x11
=（2/5+1/5x7）+1/7x9+1/9x11
=3/7+1/7x9+1/9x11
=（3/7+1/7x9）+1/9x11
=4/9+1/9x11
=5/11

x8+x7+x6+x5+x4+x3+x2+x+1因式分解 1x2/1+2x3/1+3x4/1+4x5/1+5x6/1+6x7/1 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+1/6x7 (2X2)/1X3+(4X4)/(3X5)+(6X6)/(5X7)+...+(20X20)/(19X21)==? 计算：1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+1/6x7+1/7x8+1/8x9+1/9x10. 2x2/1x3+4x4/3x5+6x6/5x7+8x8/7x9+10x10/9x11+12x12/11x13 仔细看看 1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101 1.如果1+X+X2+X3=0,求X+X2+X3+X4+X5+X6+X7+X8的值为? 一道数学题:如果1+x+x2+x3=0,求x+x2+x3+x4+x5+x6+x7+x8的值因式分解:X15+X14+X13+X12+X11+X10+X9+X8+X7+X6+X5+X4+X3+X2+X+1 某同学做一道数学题：当x=-1时，求10x9+9x8+8x7+7x6+6x5+5x4+4x3+3x2+2x+1的值，由于小明做一道数学题，“求代数式10x9+9x8+8x7+7x6+6x5+5x4+4x3+3x2+2x+1，当x=-1时的值