Matrix, Find determinant using properties of Det.

In summary, to show that (b-a)(c-a)(c-b) is equal to the determinant of the given 3x3 matrix, we can start by subtracting the first column from the second and third columns. Then we can use an expansion by minors to simplify the equation. Finally, we can use the property of determinants to find the solution.
  • #1
am_knightmare
9
0

Homework Statement


1 1 1
a b c = (b-a)(c-a)(c-b)
a^2 b^2 c^2
(above is a 3x3 matrix equaling to a equation)
question:"Show by applying property of the determinant"

Homework Equations


N/A

The Attempt at a Solution


read through the whole chapter of determinants, there were no similar problems. read it the second time focusing on properties, no simimlar properties, Please help.
 
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  • #2
Start by subtracting the first column from the second and third columns. Then think about an expansion by minors.
 
  • #3
Just solved it. thanks for the reply though.
1 1 1
a b c
a^2 b^2 c^2
becomes
1 0 0
a b-a c-a
a^2 (b^2-a^2) (c^2-a^2)
then becomes
(b-a)(c-a) times
1 0 0
a 1 1
a^2 b-a c-a
then
1 0 0
a 1 0
a^2 b-a c-b
det= 1 x 1 x(c-b) ( c-a) (b-a)
 
  • #4
am_knightmare said:
Just solved it. thanks for the reply though.
1 1 1
a b c
a^2 b^2 c^2
becomes
1 0 0
a b-a c-a
a^2 (b^2-a^2) (c^2-a^2)
then becomes
(b-a)(c-a) times
1 0 0
a 1 1
a^2 b-a c-a
then
1 0 0
a 1 0
a^2 b-a c-b
det= 1 x 1 x(c-b) ( c-a) (b-a)

Yup. That'll do it.
 

What is a matrix?

A matrix is a rectangular array of numbers or symbols arranged in rows and columns. It is used in mathematics and science to represent and manipulate data.

What is the determinant of a matrix?

The determinant of a matrix is a value that can be calculated from the elements of the matrix. It is a measure of the matrix's size and orientation, and is used in many mathematical operations such as finding inverses and solving systems of equations.

How do I find the determinant of a matrix?

There are multiple methods for finding the determinant of a matrix, but one common way is to use the properties of determinants. These properties include multiplying a row by a scalar, adding a multiple of one row to another row, and swapping two rows. By using these properties, the determinant can be simplified to a simpler form that is easier to calculate.

Why is the determinant important?

The determinant is important because it is used in many mathematical operations, such as finding inverses, solving systems of equations, and calculating volumes of parallelepipeds. It also has geometric interpretations, such as determining the orientation of a set of vectors in space.

Can the determinant of a matrix be negative?

Yes, the determinant of a matrix can be negative. This usually occurs when there is an odd number of row swaps during the calculation of the determinant. However, the sign of the determinant does not affect its value, and it is still considered a valid measure of the matrix's size and orientation.

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