先观察,再计算1-1/2=2/1x2-1/1x2=1/2 1/2-1/3=3/2x3-2/2x3=1/2x3=1/6 1
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:2024/05/29 06:31:16
先观察,再计算
1-1/2=2/1x2-1/1x2=1/2 1/2-1/3=3/2x3-2/2x3=1/2x3=1/6 1/3-1/4=4/3x4-3/3x4=1/3x4 .观察上面式子的特征,你能计算1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72吗?
1-1/2=2/1x2-1/1x2=1/2 1/2-1/3=3/2x3-2/2x3=1/2x3=1/6 1/3-1/4=4/3x4-3/3x4=1/3x4 .观察上面式子的特征,你能计算1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72吗?
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
=1-1/2+1/2-1/3+1/3-1/4+……+1/8-1/9
=1-1/9
=8/9
=1-1/2+1/2-1/3+1/3-1/4+……+1/8-1/9
=1-1/9
=8/9
求线性方程组 x2-x3-x4=0 x1+x2-x3+3x4=1 x1-x2+x3+5x4=-1 x1+2x2-2x3+
因式分解(1+x+x2+x3)2-x3
先观察,再计算1-1/2=2/1x2-1/1x2=1/2 1/2-1/3=3/2x3-2/2x3=1/2x3=1/6 1
解方程组X1+X2+X3=0,2X2-X3=1,X1-X2+2X3=-1.
已知x2+3x2+1=0,求x3+x3分之一+2的值
X1+2X2-X3+X4=1
求非齐次线性方程组:2x1-x2+4x3-3x4=-4;x1+x3-x4=-3;3x1+x2+x3=1;7x1+7x3-
用列主元Gauss消元法解线性方程组{-x2-x3+x4=0,x1-x2+x3-3x4=1,2x1-2x2-4x3+6x
已知X1+x2+X2+...+Xn=1,证明不等式:X1^2/(X1+X2)+X2^2/(X2+X3)+X3^2/(X3
x2+x=1求x3+2x2-7
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