Determinant of Skew-Symmetric Matrix: Is it Zero for Odd n?

In summary, A square matrix is skew-symmetric if its transpose is equal to its negative. For an odd value of n, if A is skew-symmetric, then its determinant is equal to 0. This is not necessarily true for even values of n.
  • #1
bmb2009
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Homework Statement



A square (nn) matrix is called skew-symmetric (or antisymmetric) if AT =
-A. Prove that if A is skew-symmetric and n is odd, then detA = 0. Is this true
for even n?

Homework Equations


Det(A) = Det(AT) where AT= the transpose of matrix A


The Attempt at a Solution


I started to try and say that since AT=-A then Det(AT) = Det(-A) so Det(A) = Det(-A) b/c the law that Det(A)=Det(AT) but I didnt know where to go from here.. specifically what impact does the odd number of n have to do with anything.. Any help
 
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  • #2
and I assume that I need to say that Det(-A) = -Det(A) for the odd number on n so then I could conclude 2Det(A)=0 but i don't see why: Det(-A) = -Det(A) is true for odd number n matrices
 
  • #3
You can easily calculate det(-I), no?? (where I is the identity matrix)
Then you can write det(-A)= det((-I)A).
 

1. What is a determinant proof?

A determinant proof is a mathematical method used to prove a statement or theorem involving determinants, which are mathematical objects that represent certain properties of matrices. It involves using specific properties and operations of determinants to manipulate equations or matrices in order to show that a statement is true.

2. Why are determinant proofs important?

Determinant proofs are important because they allow us to prove statements and theorems involving determinants, which are essential tools in linear algebra and other branches of mathematics. They also help us understand the underlying properties and relationships between matrices and their determinants.

3. What are some common properties used in determinant proofs?

Some common properties used in determinant proofs include the multiplication property, where a scalar multiple of a row or column is multiplied by the determinant; the addition property, where a multiple of one row or column is added to another row or column; and the transpose property, where the determinant of a matrix is equal to the determinant of its transpose.

4. Can you give an example of a determinant proof?

Sure, one example of a determinant proof is proving that the determinant of a product of two matrices is equal to the product of their determinants. This can be done by expanding the determinant of the product using the properties of determinants and showing that it is equal to the product of the individual determinants.

5. Are there any resources for learning more about determinant proofs?

Yes, there are many resources available for learning more about determinant proofs, including textbooks, online tutorials, and video lectures. It is also helpful to practice solving different types of determinant proofs on your own to gain a deeper understanding of the concept.

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