Give a good explanation of determinants?

In summary, the conversation discussed the importance and interpretation of determinants in mathematics and their application in various fields. The determinant of an NxN matrix represents the oriented volume of the N-parallelepiped defined by the N column vectors (or alternatively, the N row vectors) of that matrix. Various sources were recommended for a better understanding of determinants, including the book "Analysis on Manifolds" by Munkres.
  • #1
nobahar
497
2
I don't think this goes under H/W questions, as it's not a specific question needing solving, or a proof, etc.
Getting back to the point, anyone know any good websites or sources that give a good explanation of determinants? I mean what they do, why they do it, not just how to do it. I googled and got pretty boring stuff that tended to be either simply how to do them or just...well... lacking excitment.
Thanks!
 
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  • #2


Try to understand the formal properties (multilinearity) in terms of the interpretation as the volume of the parallelogram/parallelepiped (see the http://en.wikipedia.org/wiki/Determinant" ).
Determinants may not be the most exciting thing you will ever learn, but absolutely essential in almost all fields of math and applications of math.
 
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  • #3


If you want to know why the determinant does what it does, pick up 'Analysis on Manifolds' by Munkres.
 
  • #4


Cheers guys
I know what you mean by not the most exciting thing! Blimey, but I kind of get what you mean by important. I came across determinants reading about vectors.
Thanks again.
 
  • #5


The determinant of an NxN matrix is equal to the oriented volume of the N-parallelepiped defined by the N column vectors (or alternatively, the N row vectors) of that matrix.

So for example, if you have a parallelogram defined by two vectors in the plane, (1,2) and (-1,3), then the area of this parallelogram is given by

[tex]A = \left| \begin{array}{rr}1 & -1 \\ 2 & 3 \end{array} \right| = (1)(3) - (-1)(2) = 5[/tex]

which you can check geometrically, if you like.
 

1. What are determinants?

Determinants are a mathematical concept used to determine various properties of a matrix, such as its invertibility and the solution to a system of linear equations.

2. How are determinants calculated?

The determinant of a matrix is calculated by multiplying the elements in the main diagonal and subtracting the product of the elements in the opposite diagonal.

3. What is the significance of determinants?

Determinants are used in various fields of mathematics and science, including linear algebra, calculus, and physics. They are also important in solving systems of equations and finding the area and volume of geometric shapes.

4. Can determinants be negative?

Yes, determinants can be negative. The sign of the determinant depends on the number of row or column swaps that are performed during the calculation of the determinant.

5. How do determinants relate to eigenvalues?

Determinants and eigenvalues are closely related. The eigenvalues of a matrix can be found by solving the characteristic equation, which is formed using the determinant of the matrix. In other words, the determinant helps us find the eigenvalues of a matrix.

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