Calculate the determinant of a 3x3 matrix with variables x, y, and z.

Published on February 23, 2025

Linear-Algebra

The determinant is evaluated by splitting it into two parts, factoring out terms, and using the Vandermonde determinant formula. The final result is expressed as a product of factors involving x, y, and z, and a term (1-xyz).

Question

Answer

We are asked to evaluate the determinant:
We can split the determinant along the third row:
Let and . Then .
For , we can factor out from the first column, from the second column, and from the third column:
This is a Vandermonde determinant, and its value is .
So, .
For , we can factor out from the third row:
Swap the first and third rows:
Swap the second and third rows:
Thus, .
Therefore, .
Since , we have
.
So, .
Final Answer: The final answer is