1/2+1/6+1/12+1/20+1/30+1/42+1/56 ; 1/1x3+1/3x5+1/5x7+1/7x9+1
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/07/17 15:58:20
1/2+1/6+1/12+1/20+1/30+1/42+1/56 ; 1/1x3+1/3x5+1/5x7+1/7x9+1/9x11+1/11x13
1/2+1/6+1/12+1/20+1/30+1/42+1/56 =1/(1*2)+1/(2*3)+1/(3*4)+.+1/(7*8) =1-1/2+1/2-1/3+1/3-1/4...+1/7-1/8 =1-1/8 =7/8 补充:1/1x3+1/3x5+1/5x7+1/7x9+1/9x11+1/11x13 =1/2*(1-1/3+1/3-1/5+1/5-1/7...+1/77-1/13) =1/2*(1-1/13) =1/2*12/13 =6/13
2/1x3+2/3X5+2/5x7=2/7x9+2/9x11
1/1x3+1/3x5+1/5x7+1/7x9+1/9x11=?
1+2X3+4X5+6X7+8X9=303
计算:1/1x3+1/3x5+1/5x7+1/7x9+……+1/2011x2013
1X3分之一+3X5分之一+5X7分之一+7X9分之一加到2009X2011分之一怎么算,
2x2/1x3+4x4/3x5+6x6/5x7+8x8/7x9+10x10/9x11+12x12/11x13 仔细看看
已知1-1/3=2/1x3,计算1/1x3+1/3x5+1/5x7+1/7x9+1/9x11=
计算:1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+1/6x7+1/7x8+1/8x9+1/9x10.
因式分解:X15+X14+X13+X12+X11+X10+X9+X8+X7+X6+X5+X4+X3+X2+X+1
给1+2x3+4x5+6x7+8x9=1005这道式子加上小括号 中括号 大括号使式子成立.
给1+2x3+4x5+6x7+8x9=1717这道式子加上小括号 中括号 大括号使式子成立.
给1十2x3十4x5十6x7十8x9=505加上小括号、中括号、大括号、使算式成立.