为什么1/2+5/6+11/12+19/20+…………+89/90 的规律是1X2.2X3.3X4.4X5.5X6.6X
1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101
1/1X2+1/2X3+1/3X4+1/4X5+1/5X6……1/2007X2008
(2X2)/1X3+(4X4)/(3X5)+(6X6)/(5X7)+...+(20X20)/(19X21)==?
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+8x8/7x9+10x10/9x11+12x12/11x13 仔细看看
①数据X1、X2、X3的平均数是2,数据X4、X5、X6、X7、X8的平均数是6,则数据X1、X2、X3、X4、X5、X
已知数据X1,X2,X3,X4,X5的平均数是X拔,则一组新数据X1+1,X2+2,X3+3,X4+4,X5+5的平均数
用秦九韶算法计算当X=3时多项式f(x)=7X7+6x6+5x5+4x4+3X3+2x2+X的值
真倒霉!上次提这个问题花了我20分,结果没提上去!题目是这样的:1x1-2x2+3x3-4x4+5x5-6x6+...+
1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+......1/2008x2009
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