Proving a formula for the determiante in a special matrix

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SUMMARY

The discussion centers on proving the determinant of a specific matrix involving real numbers a1, a2, ..., an, where n > 1. The determinant is established as the product of differences between pairs of these numbers, specifically expressed as \prod (aj - ai) for 1 ≤ i < j < n. Participants explored induction methods for proving this formula, confirming that the right-hand side matches the determinant's calculated value. The conversation concludes with a consensus that the derived formula accurately represents the determinant of the matrix.

PREREQUISITES
  • Understanding of matrix determinants and properties
  • Familiarity with mathematical induction techniques
  • Knowledge of row reduction methods for matrices
  • Basic concepts of real numbers and their properties
NEXT STEPS
  • Study advanced techniques in proving determinants, such as Laplace's expansion
  • Learn about the properties of determinants in relation to matrix transformations
  • Explore the application of induction in mathematical proofs
  • Investigate the implications of determinants in linear algebra and systems of equations
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Students and educators in mathematics, particularly those focusing on linear algebra, matrix theory, and mathematical proofs. This discussion is beneficial for anyone seeking to deepen their understanding of determinants and their applications.

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Homework Statement



Let a1, a2 are real numbers, where n > 1 show that: determinant of:

| 1 a1 a21 ... ... an-11 |
| 1 a2 a22 ... ... an-12 |
:
:
| 1 an a2n ... ... an-1n |


= [tex]\prod[/tex] (aj - ai)
1[tex]\leq[/tex]i<j<n

Homework Equations


if you row reduce a matrix the determinate is the product of the leading diagonal(previous question was finding determinate of matrices by row reducing them)

The Attempt at a Solution


tried using induction but get stuck very quickly.
i got RHS =
= [tex]\Pi[/tex]0<i<j<n (aj - ai) [tex]\Pi[/tex]0<k<n (an - ak)
 
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rosh300 said:
show that: determinant of …
= [tex]\prod[/tex] (aj - ai)
1[tex]\leq[/tex]i<j<n

i got RHS =
= [tex]\Pi[/tex]0<i<j<n (aj - ai) [tex]\Pi[/tex]0<k<n (an - ak)

Hi rosh300! :smile:

But that's the answer, isn't it?

The first part is all non-identical pairs up to n-1, and the second part is all non-identical pairs of which the higher is n.
 

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