1X2/5+2X3/5+3X4/5+4X5/5.+48X49/5+49X50/5=?
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1X2/5+2X3/5+3X4/5+4X5/5.+48X49/5+49X50/5=?
1X2/5+2X3/5+3X4/5+4X5/5.+48X49/5+49X50/5=?
1X2/5+2X3/5+3X4/5+4X5/5.+48X49/5+49X50/5=?
1X2/5+2X3/5+3X4/5+4X5/5.+48X49/5+49X50/5=?
=5(1-1/2)+5(1/2 -1/3)+5(1/3-1/4)+5(1/4-1/5)+.+5(1/48-1/49)+5(1/49-1/50)
=5(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+.+1/48-1/49+1/49-1/50)
=5(1-1/50)
=5*(49/50)
=49/10
=4.9
课一把上述式子看成一个数列,则它的通项公式是An=n(n+1)/5=n^2/5+n/5,所以就可把它看成一个等比数列n^2/5和一个等差数列n/5之和
思路有了,剩下的就是你的计算了
(2x4-5x2-4x+1)-(3x3-5x2-3x)
用矩阵法姐方程组:2x1-3x2 +x 3-x4 =3 3x 1+x2 +x3 +x 4=0 4x1 -x2 -x 3-x4 =7 -2x 1-x3 +x3 +x4 =-5
x4-x3-5x2-6x-4
用初等行变换来解下列线性方程组(1)2x1-x2+3x3=3 3x1+x2-5x3=0 4x1-x2+x3=3 x1+3x2-13x3=-6(2) x1-2x2+x3+x4=1 x1-2x2+x3-x4=-1 x1-2x2+x3-5x4=5(3) x1-x2+x3-x4=1 x1-x2-x3+x4=0 x1-x2-2x3+2x4=-1/2
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
非齐次线性方程组求解.x1+x2+2x3+3x4=1 2x1+3x2+5x3+2x4=-3 3x1-x2-x3-2x4=-4 3x1+5x2+2x3-2x4=-10
讨论2X1+X2-X3+X4=1 3X1-2X2+2X3-3X4=2 5X1+X2-X3+2X4=-1 2X1-X2+X3-3X4=4的解的情况
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
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
分解因式:-27x3+8 ,(x2-5x+2)(x2-5x+4)-24 ,x5+x4+x3+x2+x1+1
下列方程组如何解 2x1+x2-2x3+3x4=1 3x1+2x2-x3+2x4=4 3x1+3x2+3x3-3x4=52x1+x2-2x3+3x4=13x1+2x2-x3+2x4=43x1+3x2+3x3-3x4=5如何解这个线性方程组,因为不太懂。
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
1.用基础解系表示线性方程组的通解X1 +2X2+3X3-X4=13X1+2X+X3-X4=1 2X1+3X2+X3+X4=12X1+2X2+2X3-X4=15X1+5X2+2X3=22.3 1 0A= -4 -1 0 的特征值和特征向量.4 -8 2 1.用基础解系表示线性方程组的通解X1 +2X2+3X3-X4=13X1+2X2+X3-X
6x4+5x3+3x2-3x+2因式分解
分解因式:x4-x3+4x2+3x+5
用消元法解方程组x1+x2-2x2=-3,5x1-2x2+7x3=22.2x1-5x2+4x3=4 是字母x.x1+2x2-x3-2x4=0,2x1-x2-x3+x4=1,3x1+x2-3x3-x4=1
{2X1-X2+3X3=33X1+X2-5X3=04X1-X2+X3=3X1+3X2-13X3=-6{X1-2X2+3X3-4X4=4X2-X3+X4=-3X1+3X2-3X4=1-7X2+3X3+X4=-3
之 多项式的除法运算分解这几个多项式x4 是指x的四次方。依此 x3就是x的三次方x4-x3-43x2+x+42 第2题 x4+4x3-27x-108 第3道 2x4-25x3+57x2+9x+405 第4道 x4+13x3+40x2+81x+405第5道 x4+3x3-4x2+3x-135 第6道 x4+4x3-35x2-78x