The multiplication of matrices is equal to the multiplication of their determinants It's not directly shown in the book But in the process of doing the questions, I found that it seems that this can work

The multiplication of matrices is equal to the multiplication of their determinants It's not directly shown in the book But in the process of doing the questions, I found that it seems that this can work

Matrix multiplication, the result is matrix. Their determinant multiplication, the result is a number. Obviously can't compare, can't say equal not equal
However, the determinant of matrix multiplication is equal to the matrix determinant multiplication
For example, matrices A and B have the following equation:
|AB|=|A||B|
How to multiply the determinants of one row, two columns and one column, two rows
(- 10, - 4)] and 4
〖 〗
Ten
This is matrix multiplication, not determinant
1 * 2 matrix multiplied by 2 * 1 matrix, the result is a 1 * 1 matrix, that is, a number
(-10,-4)(4,10)^T = -10*4 -4*10 = 80.
. 4 -10*4 -4*4 -40 -16
-10.-4× = =
10 -10*10 -4*10 -100 -40
How to say that a determinant is divided into multiple multiplication forms
It's using | ab | = | a | B|
You can refer to the solution of this determinant:
How to prove that the determinant of block diagonal matrix is equal to the multiplication of block determinant?
If every submatrix is transformed into an upper (lower) triangular matrix by row (column) transformation, then the large matrix is transformed into an upper (lower) triangular matrix, then the determinant of the large matrix is equal to the product of the elements on the main diagonal, and the determinant of every submatrix is equal to the product of the elements on the main diagonal of their upper (lower) triangular matrix. That is, the determinant of block diagonal matrix is equal to the multiplication of block determinants
Proof by Laplace expansion of determinant
Then the analytic function (x + 1) is not parallel to this point?
If the image of the first-order function y = KX + B (not equal to 0) passes through the point (1. - 1) and is parallel to the straight line 2x + y = 5, the solution of the first-order function will write out the solution steps
Because the image of the linear function y = KX + B (not equal to 0) is parallel to the line 2x + y = 5
So: k = - 2
And because the image of the linear function y = KX + B (not equal to 0) passes through the point (1. - 1)
So - 1 = k * 1 + B
So: B = 1
So the analytic formula of a function is as follows:
y=-2x+1
Two lines are parallel, so k = 2, and then take the point in
For nonempty sets a and B, define the operation: a ⊕ B = {x | x ∈ a ∪ B, and X ∉ a ∩ B}, M = {x | a ＜ x ＜ B}, n = {x | C ＜ x ＜ D}, where a, B, C and D satisfy a + B = C + D, ab ＜ CD ＜ 0, then m ⊕ n = ()
A. （a，d）∪（b，c）B. （c，a]∪[b，d）C. （c，a）∪（d，b）D. （a，c]∪[d，b）
We know that M = {x \\\124;a \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\∪ [D] ∪ [D] ∪ [D] ∪ [D] ∪ [D] So D
Given the equation of X, the solution X of 5x-2m = 3x-6m + 1 satisfies - 3 > x > = 2, and the integer value of M is obtained
3∠x≤2,
-6∠2x≤4,
5x-2m=3x-6m+1
2x=1-4m
-6
The limit rule,
In the face of the solution of infinity in the form of infinity over infinity, who can give an example to illustrate it
LIM (x tends to infinity) (x ^ 2-3x) / (2x ^ 2 + 1) molecule, denominator divided by x ^ 2 = LIM (x tends to infinity) (1-3 / x) / (2 + 1 / x ^ 2) = (1-0) / (2 + 0) = 1 / 2,
Given that the equations 4x-y = 5, ax + by = - 1 have the same solution as the equations 3x + y = 9, 3ax + 4BY = 18, find the values of a and B
Quick, the most concise!
According to the meaning of the title, 4x-y = 5, ① 6x + 2Y = 18, ② ax + by = - 1, ③ 3ax + 4BY = 18, ④ ① * 2 + ② can get 14x = 28, x = 2, substituting x = 2 into ①, y = 3, substituting x = 2, y = 3 into ③, ④ can get 2A + 3B = - 1, ⑤ 6A + 12b = 18, ⑥, ⑤ * 4 - ⑥ can get 2A = - 22, a = - 11, substituting a = - 11 into ⑤, 2 *
The simplest answer is a = - 8 / 3. B = 2 / 7
Because two systems of equations have the same solution
So 4x-5 = y, 9-3X = y
So 4x-5 = 9-3X
We get x = 2, y = 3. Substituting the original formula, we get 2A + 3B = - 1, 6a + 12b = 18
Combining the two formulas, a = - 11, B = 7
If the image of a linear function y = KX + B (K ≠ 0) passes through a point (1, - 1) and is parallel to a straight line y = - 2x + 5, the analytic expression of the linear function is______ .
∵ the image of the first-order function y = KX + B (K ≠ 0) is parallel to the straight line y = - 2x + 5, ∵ k = - 2; ∵ the image of the first-order function y = KX + B (K ≠ 0) passes through the point (1, - 1), ∵ 1 = - 2 + B, the solution is b = 1; ∵ the analytic expression of the first-order function is y = - 2x + 1; so the answer is: y = - 2x + 1