1/2x5+1/5x8+1/8x11+.+1/2006x2009+2009x2013用裂项法计算
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1/2x5+1/5x8+1/8x11+.+1/2006x2009+2009x2013用裂项法计算1/2x5+1/5x8+1/8x11+.+1/2006x2009+2009x2013用裂项法计算1/2x
1/2x5+1/5x8+1/8x11+.+1/2006x2009+2009x2013用裂项法计算
1/2x5+1/5x8+1/8x11+.+1/2006x2009+2009x2013用裂项法计算
1/2x5+1/5x8+1/8x11+.+1/2006x2009+2009x2013用裂项法计算
=1/3*(1/2-1/5)+1/3*(1/5-1/8)+.+1/3*(1/2006-1/2009)+1/3*(1/2009-1/2013)
=1/3*(1/2-1/5+1/5-1/8+.+1/2006-1/2009+1/2009-1/2013)
=1/3*(1/2-1/2013)
=1/3*1/2011
=1/6033
an = 1/[(3n-1)(3n+2)]
= (1/3)[ 1/(3n-1) - 1/(3n+2)]
Sn = a1+a2+...+an
= (1/3) [ 1/2 - 1/(3n+2) ]
1/(2x5)+1/(5x8)+1/(8x11)+...+1/(2006x2009)+1/(2009x2013)
= S670
= (1/3) ( 1/2 - 1/2012)
=335/2012
1/2x5+1/5x8+1/8x11+.+1/2006x2009+2009x2013用裂项法计算
裂项法1/2X5+1/5x8+1/8x11.1/2009x2012=?
1/2x5 +1/5x8 +1/8x11+……+1/2009x2012=?
1/2x5+1/5x8+1/8x11+1/11x14+1/14x17+1/17x20
2x5/1+5x8/1+8x11/1+.2006x2009/1+2009x2012/1 用裂项法计算
1/2x5+1/5x8+1/8x11+.+1/32x35要有 详细的算式方法
1x2+2x3+3x4+4x5+5x6+6x7+7x8+8x9+9x10+10x11
数列1/2X5,1/5X8,1/8X11,、、、1/[（3N-1）X（3N+2）]的前N项和是
2 1/2x5+4 1/5x8+6 1/8x11+...+100 1/149x150+102 1/152x155那个事带分数，
1x2+2x3+3x4+4x5+5x6+6x7+7x8+8x9+9x10+10x11+ +nx(n+1)=
3/2X5+3/5X8+3/8X11+.+3/1997X2000+3/2000X2003=
数学建模的LINGO使用问题modelmin=x0+x11+x8+x9;x0+x1+x2+x3+x4+x5+x6+x7+x8+x9+x10+x11=11;x0+x1+x3+x4>=4;x1+x2+x4+x5>=4;x2+x3+x5+x6>=4;x3+x4+x6+x7>=3;x4+x5+x7+x8>=3;x5+x6+x8+x9>=4;x6+x7+x9+x10>=4;x7+x8+x10+x11>=2;x8+x9+x11+x0>=2;x9+x10+x0+x1>=1;
1/1/10+3/1/40+5/1/88+9/1/154简算原题。1/1/2x5+3/1/5x8+5/1/8x11+9/1/11x14简算
(1-1/2x4)x(1-3/3x5)x(1-5/4x6)x(1-7/5x7)x(1-9/6x8)x(1-11/7x9)x(1-13/8x10)x(1-15/9x11)
1又2x5分之1+3又5x8分之1+5又8X11分之1+7又11x14分之1+9又14x17分之1+11又17x20分之1=（写出过程）
1/2x5+1/5x8+1/8x11+…………+1/2003x2006+1/2006x2009 = 这是我儿子的小学作业,我想不出简便算法……
2x2/1x3+4x4/3x5+6x6/5x7+8x8/7x9+10x10/9x11+12x12/11x13 仔细看看 给50啊
1/5x8+1/8x11+1/11x14+.+1/98x101=1/(5x8)+1/(8x11)+1/(11x14)+.+1/(98x101)