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: Scaling a row scales the determinant

  1. Nov 17, 2012 #1
    1. The problem statement, all variables and given/known data
    http://puu.sh/1rcsO [Broken]

    I got the first one from a simple scaling, but I can not figure out the second one.

    2. Relevant equations
    Det(cA) = cDet(A)
    Scaling a row scales the determinant
    Adding rows/columns to each other does not affect the determinant
    Det(AT) = Det A

    3. The attempt at a solution
    So, shouldn't I be able to scale http://puu.sh/1rcyZ [Broken] by -2, and just add row 2 and row 3 by multiples of row 1 ? I actually don't even think this is even close to right because the column 1 and 3 won't resemble each other at all once the row operations are done...
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Nov 17, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper

    Hi Lifprasir! :smile:

    Hint: what are the gaps between 1,2,3?

    what are the gaps between -2,-8,-14? :wink:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook