1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Lower triangular matrix

  1. Mar 28, 2010 #1
    1. The problem statement, all variables and given/known data
    I keep trying to turn a 4x4 matrix into a lower triangular matrix and then multiply along the diagonal to get the determinant , but I cant get the answer in the back of the book , is there some property about determinates I am missing .
     
  2. jcsd
  3. Mar 28, 2010 #2

    Mark44

    Staff: Mentor

    Hard to say without seeing your work.

    BTW, the word is determinant.
     
  4. Mar 28, 2010 #3
    ok as long as we add rows together it doesn't change the det(A)
    i can go 5R1+R2=R2 and it wont change the det(A) correct.
     
  5. Mar 28, 2010 #4

    Mark44

    Staff: Mentor

    Right. Of the three row operations, the only ones that change the value of the determinant are replacing a row by a multiple of itself (Rn <-- k*Rn) and switching two rows (Rn <--> Rm).
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook