1X2/1+2X3/1+3X4/1+……+9X10/1=_____
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1X2/1+2X3/1+3X4/1+……+9X10/1=_____
![1X2/1+2X3/1+3X4/1+……+9X10/1=_____](/uploads/image/z/19841348-20-8.jpg?t=1X2%2F1%2B2X3%2F1%2B3X4%2F1%2B%E2%80%A6%E2%80%A6%2B9X10%2F1%3D_____)
是1/(1*2)+1/(2*3)+1/(3*4)+.+1/(9*10)吧
1/(1*2)+1/(2*3)+1/(3*4)+.+1/(9*10)
=(1/1-1/2)+(1/2-1/3)+……+(1/9-1/10)
=1-1/2+1/2-1/3+……+1/9-1/10
=1-1/10
=9/10
1/(1*2)+1/(2*3)+1/(3*4)+.+1/(9*10)
=(1/1-1/2)+(1/2-1/3)+……+(1/9-1/10)
=1-1/2+1/2-1/3+……+1/9-1/10
=1-1/10
=9/10
1/1x2+1/2x3+1/3x4+1/4x5.1/9x10简算
已知:x1=1/2+1/3,x2=1/3+1/4,x3=x2+x1,x4=x3+x2.,x10=x9+x8,求:x7/x
求线性方程组 x2-x3-x4=0 x1+x2-x3+3x4=1 x1-x2+x3+5x4=-1 x1+2x2-2x3+
X1+2X2-X3+X4=1
计算①1x2/1+2x3/1+3x4/1+```+19x20/1= ②1x4/1+4x7/1+7x10/1+```+91
求齐次线性方程组x1+2x2+x3+x4+x5=1 2x1+4x2+3x3+x4+x5=2 -x1-2x2+x3+3x4
设线性方程组(x1+2x2-2x3+2x4=2,x2-x3-x4=1 x1+x2-x3+3x4=a)
具体写出方程组:2x1+x2-x3+x4=1;x1+2x2+x3-x4=2;x1+x2+2x3+x4=3的通解
解方程组X2+X3+X4=1 X1+X2+X3=5 X3+X4+X5=-5 X4+X5+X1=-3 X5+X1+X2=2
1+x+x2+x3+x4=0,那1+x+x2+x3+x4+……+x2004=?
1+2x4-(x2+2x3)
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