1/1X3+1/2X4+1/3X5+.+1/18X20=?
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/07/08 20:11:37
1/1X3+1/2X4+1/3X5+.+1/18X20=?
![1/1X3+1/2X4+1/3X5+.+1/18X20=?](/uploads/image/z/18101906-26-6.jpg?t=1%2F1X3%2B1%2F2X4%2B1%2F3X5%2B.%2B1%2F18X20%3D%3F)
1/1X3=1/2(1/1-1/3)
1/2*4=1/2(1/2-1/4)
.
1/1X3+1/2X4+1/3X5+.+1/18X20
=1/2(1/1-1/3+1/2-1/4+1/3-1/5+.+1/18-1/20)
=1/2(1/1+1/2-1/19-1/20)
=531/760
1/2*4=1/2(1/2-1/4)
.
1/1X3+1/2X4+1/3X5+.+1/18X20
=1/2(1/1-1/3+1/2-1/4+1/3-1/5+.+1/18-1/20)
=1/2(1/1+1/2-1/19-1/20)
=531/760
(2X2)/1X3+(4X4)/(3X5)+(6X6)/(5X7)+...+(20X20)/(19X21)==?
解方程组X2+X3+X4=1 X1+X2+X3=5 X3+X4+X5=-5 X4+X5+X1=-3 X5+X1+X2=2
求齐次线性方程组x1+2x2+x3+x4+x5=1 2x1+4x2+3x3+x4+x5=2 -x1-2x2+x3+3x4
求解一个方程急 X(1次方)+X2+X3=5 X2+X3+X4=1 X3+X4+X5=-5 X4+X5+X1=-3 X5
解一道方程组x1+x2+x3=5,x2+x3+x4=1,x3+x4+x5=-5,x4+x5+x1=-3,x5+x1+x2
X5-X4+X3+X2+X+1因式分解
x5-x4+x3-x2+x-1因式分解
1分解因式:2x4-x3-13x2-15=?2.分解因式:x5+x4+x3+x2+x+1=?3分解因式:x4-4x2+6
1/1x2+1/2x3+1/3x4+1/4x5+```````+1/2008x2009=?
1/1x2+1/2x3+1/3x4+1/4x5.1/2005x2006=?
式子如下:1 1 1 1 1--- + --- + --- + --- + .+ ---- = 2x3 3x4 4x5
计算①1x2/1+2x3/1+3x4/1+```+19x20/1= ②1x4/1+4x7/1+7x10/1+```+91