77问答网
所有问题
当前搜索:
x1-x2+4x3=2
X1+X2+
X3+X4=1;3X1+2X2-X3-X4=0;
X2+4X3
+4X4=3解线性方程组怎么算?_百 ...
答:
r(A, b) = r(A)
= 2
< 4, 方程组有无穷多解。方程组化为
x1
= -
2 +
3x3 + 3x4
x2
= 3 -
4x3
- 4x4 取
x3 =
x4 = 0, 得 AX = b 特解 (-2, 3, 0, 0)^T;导出组为 x1 = 3x3 + 3x4 x2 = - 4x3 - 4x4 取 x3 =1, x4 = 0, 得 AX = 0 ...
两直线
X1+
2
X2
-
4X3=
0与2X1-X2+X3=0交点坐标与方程,其中X都是未知数...
答:
方程通式aX+bY+cZ=0;法向量为(a,b,c);法向量分别为m=(1,2,-4),n=(2,-1,1)交线的方向向量s=m*n'=(2,4,-8)取
x1=2
,则
x2
=9,
x3=
5,两平面都经过(2,9,5),即该点在交线上.交线方程(x1-2)/2=(x2-9)/4=(x3-5)/-8 ...
用消元法解线性方程
X1
+2X2+3X3=4 3
X1
+5X2+7X3=9 2X1+3
X2+4X3=
5?_百 ...
答:
X1+2X2+3X3=4 .(1)3X1+5X2+7
X3=
9.(2)2X1+3X2+
4X
3=5.(3),(1)+(2)-(3)*2,得:
X2+
2X3=3 即:X
2=
3-2
X3
,代入(1):得:
X1=
X3-2,所以,该方程组的解为:X1=t-2 X2=3-2t X3=t.,3,1,
x²
+4x
-
3=
0
答:
X²
+4X
—
3=
0 解:X²+4X=3 X²+4X+4=3+4 (X+2)²=7 X+2=±√7 ∴X+2=√7或X+2=—√7
X1
=—
2+
√7
X2
=—2—√7
解线性方程组
x1+
2x2+3x3+4x4=5 2x1+4x2
+4x3
+6x4=8 -x1-2
x2
-x3-2x4=...
答:
-
x1
-2
x2
- x3-2x4=-3 (3)(1)+(3)2x1+4x2
+4x3
+6x4=8 = equation(2)Rank of system of equtions
= 2
(1)+2(3)-x1-2x2+
x3=
-1 x3= x1+2x2-1 (4)sub (4) into (3)-x1-2x2- (x1+2x2-1)-2x4=-3 x4= -x1-2x2 +2 solution of system of equations (x1,x2...
x²
+4x
-
2=3
答:
解:x^
2+4x
-2=3 x^
2+4x
-2-
3=
0 x^2+4x-5=0 (
x-1
)(x+5)=0 x-1=0或x+5=0
x1
=1,
x2=
-5 所以原方程的解为x1=1,x2=-5
设
x1
、x2是
二
次方程
x2+
x-
3=
0的两个根,求x1的三次方-4倍的x2的平方+202...
答:
x1^
3+x1
^2-3x1=0,x1^
3=
3x1-x1^2
x1+x2=
-1 (1)x1*x2=-3 (2)(1)^2 x1^2+x2^2+2x1x2=1 (2)代入 x1^2+x2^2=7 4x2^2=27-4x1^2 x1^3-4x2^2+2028=x1^3-27+4x1^2+2028 =x1^3+4x1^2+2001 =3x1-x1^
2+4x
1^2+2001 =3x1^2+3x1+2001 =3(x1^2+x1)+...
...
X1+X2
-2*X4=-6 4*
X1-X2
-X3-X4=1 3X1-X2-
X3=
3
答:
解: 增广矩阵(A,b) = 1 1 0 -
2
-6 4 -1 -1 -1 1 3 -1 -1 0 3 r2-r1-r3, r3-3r1 1 1 0 -2 -6 0 -1 0 1 4 0 -4 -1 6 21 r1+r2,r3-4r2,r2*(-1)1 0 0 -1 -2 0 1 0 -1 -4 0 0 -1 2 5 r3*(-1)1 0 0 -1...
X1
-2X2+3
X3
-X4=1 ; 3
X1-X2+
5
X3
-3X4=4 ; 2
X1+
X2+2X3-2X4=3 ; 求解非...
答:
对方程的增广矩阵进行初等变换 1 -
2
3
-1 1 3 -1 5 -3 4 2 1 2 -2 3 将矩阵化简成对角阵 1 2 3 -1 1 0 5 -4 0 1 0 5 -4 0 1 矩阵的秩为2,因此 方程解为
X=
k1{1,1/8,0,1/4}'+k2{0,-1,1,1}' k1,k2为任意常数 ...
...
4x=
-1的两根,不解方程求下列各式的值 (1) ∣
x1-x2
∣ (2)9x13+13...
答:
所以
x1+
x2=4/3,
x1x
2=1/3.(1)|
x1-x2
|=√(x1-x2)^2 =√[(x1+x2)^2-
4x
1x2]=√(16/9-4/3)=√(4/9)
=2
/3.(2)x^2=(4x-1)/3,x^4=[(4x-1)/3]^2 =(16x^2-8x+1)/9 =(64x-16-24x+3)/27 =(40x-13)/27,x^8=[(40x-13)/27]^2 =(1600x^2-1040x...
首页
<上一页
3
4
5
6
8
7
9
10
11
12
下一页
尾页
其他人还搜