How Do Row Operations Affect a Determinant's Value?

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SUMMARY

The discussion focuses on the impact of row operations on the value of a determinant, specifically in the context of evaluating a determinant by transforming a matrix into upper triangular form. It highlights that replacing a row by a nonzero multiple of itself alters the determinant's value, alongside the operation of swapping two rows. The correct value of the determinant in the example provided is confirmed to be -17, emphasizing the importance of understanding how specific row operations affect determinant calculations.

PREREQUISITES
  • Understanding of determinant properties
  • Familiarity with row operations in linear algebra
  • Ability to manipulate matrices into upper triangular form
  • Knowledge of how row operations affect determinant values
NEXT STEPS
  • Study the effects of row operations on determinants in linear algebra
  • Learn about upper triangular matrices and their properties
  • Explore examples of determinant calculations using various row operations
  • Review the implications of swapping rows on determinant values
USEFUL FOR

Students studying linear algebra, educators teaching matrix theory, and anyone interested in mastering determinant calculations and row operations.

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Homework Statement



Evaluate the following determinant by expressing the matrix in upper triangular form.

Homework Equations



row operations.

The Attempt at a Solution



http://yfrog.com/jnscan0001ugj
http://img707.imageshack.us/img707/6379/scan0001ug.jpg
[PLAIN]http://img707.imageshack.us/img707/6379/scan0001ug.jpg

I want to know what I did wrong there cause I can't figure it out
the calculator shows a different answer.
 
Last edited by a moderator:
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In your 4th (or so) step, you replaced row 2 by 1/2 itself. Replacing a row by a nonzero multiple of itself is one row operation that changes the value of the determinant. The other row operation that does this is swapping two rows.

The correct value of the determinant is -17.
 

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