1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101

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1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101

1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101
1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101

1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101
1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101
=1^2-2^2+3^2-4^2+5^2-6^2.-100^2+101^2
=(1-2)(1+2)+(3-4)(3+4)+.(99-100)(99+100)+101^2
=-(1+2+3+4.+99+100)+101^2
=-101*50+101^2
=101*(101-50)
=5151

(1+2)(1-2)......(99+100)(99-100)+101*101
=-3-7-11-.....-199+10201
=-5050+10201
=5151

-k^2+(k+1)^2=2k+1 k=2,4,6,...,100
所以原式=1*1+2*(2+100)*50/2+50=5151

利用平方差公式:
1*1-2*2+3*3-4*4+5*5……-100*100+101*101
=1*1+(3*3-2*2)+(5*5-4*4)……+(101*101-100*100)
=1*1+(3+2)*(3-2)+(5+4)*(5-4)+……+(101+100)*(101-100)
=1+5*1+9*1+……+201*1
=1+5+9+……+201(共...

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利用平方差公式:
1*1-2*2+3*3-4*4+5*5……-100*100+101*101
=1*1+(3*3-2*2)+(5*5-4*4)……+(101*101-100*100)
=1*1+(3+2)*(3-2)+(5+4)*(5-4)+……+(101+100)*(101-100)
=1+5*1+9*1+……+201*1
=1+5+9+……+201(共有51项,成等差数列)
=(1+201)*51/2(等差数列求和公式)
=5151

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解方程组:x1+x2+x3+x4+x5=7 3x1+2x2+x3+x4-3x5=-2 x2+2x3+2x4+6x5=23 5x1+4x2-3x3+3x4-x5=10 x1-x2+x3=1 x2-x3+x4=2 x3-x4+x5=3 x4-x5+x1=4 x5-x1+x2=5 求x1,x2,x3,x4,x5 求非齐次线性方程组的通解x1+3x2+5x3-4x4=1x1+3x2+2x3-2x4+x5=-1x1-2x2+x3-x4-x5=3x1+2x2+x3-x4-x5=3 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=2 1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101 若x1,x2,x3,x4,x5满足方程组:x1-x2+x3=1 x2-x3+x4=2 x3-x4+x5=3 x4-x5+x1=4 x5-x1+x2=5 求x2,x3,x4的少打了个字,是求x2,x3,x4的值 x1-x2+x3=1x2-x3+x4=21若x1,x2,x3,x4,x5满足方程组 x3-x4+x5=3x4-x5+x1=4x5-x1+x2=5求x2 x3 x4的值2已知 x1+x4+x6+x7=39 x2+x4+x5+x7=49 x3+x5+x6+x7=41 x4+x7=13 x5+x7=14 x6+x7=9 x1+x2+x3+x4+x5+x6+x7=9求x7的值若x1,x2,x3,x4,x5满足方程组 x1-x 求解线性方程组 x1-2x2+3x3-x4-x5=2 x1+x2-x3+x4-2x5=1 2x1-求解线性方程组x1-2x2+3x3-x4-x5=2x1+x2-x3+x4-2x5=12x1-x2+x3-2x5=22x1+2x2-5x3+2x4-x5=5 求线性方程组的全部解,并用对应导出组的基础解系表示X1+3X2+5X3-4X4=1 X1+3X2+2X3-2X4+X5=-1 X1-2X2+X3-X4-X5=3 X1-4X2+X3+X4-X5=3 X1+2X2+X3-X4+X5=-1 求非其次线性方程组 {x1+2x2+x3+x4+x5=1x1+2x2+x3+x4+x5=12x1+4x2+3x3+x4+x5=2-x1-2x2+x3+3x4-x5=5 2x3+4x4-2x5=6 的一般解 求下列非齐次线性方程组的通解(1){x1+x2+x3+x4+x5=2;x1+2x2-4x5=-2;x1+2x3+2x4+6x5=6;4x1+5x2+3x3+3x4-x5=4}(2){x1-x2+5x3-x4=1;x1+x2-2x3+3x4=1;2x1+3x3+2x4=2;2x1+4x2-11x3+10x4=2}(3){x1+x2+x3+x4+x5=1;3x1+2x2+x3+x4-3x5=0 求非齐次线性方程组X1-X2-X3+X4=0,X1-X2+X3-3X4=1,2X1-2X2-4X3+6X4=-1的通解 求用matlab解方程组已知:X1+X2+X3=0.030852 0.5X1+X2+0.5X5-0.21na =0.012578 2X3+X4+X5 =0.029356 X7-0.79na =0 36.5 X2 X4= 27.156 X5 X1 12876+33723.33na=324938.80X1+68925.48 X2 + 965091.69 X3 + 323197.81 X4+ 53916.70X5 + 41341. 确定a的值,使线性方程组{X1+X2+X3+X4=1,3X1+2X2+X5+X4=0,X2+2X3+2X4=a,5X1+4X2+3X2+3X4=2 并求通解 1x1 2x2 3x3 4x4 5x5```````nxn有什么规律 1x1 2x2 格式正确 3x3 4x4 5x5 求解奇次线性方程组{上面2x1+x2+3x3+5x4-5x5 =0 中x1+x2+x3+4x4-3x5=0 下面3x1+x2+5x3+6x4-7x5=0 求方程组x1+3x2+x3+2x4+4x5=3 2x1-x2+8x3+7x4+2x5=9 4x1+5x2+6x3+11x4+10x5=15的全部解线性代数