Results 1 to 3 of 3

Math Help - [SOLVED] Determinant of a 3x3 matrix

  1. #1
    MHF Contributor arbolis's Avatar
    Joined
    Apr 2008
    From
    Teyateyaneng
    Posts
    1,000
    Awards
    1

    [SOLVED] Determinant of a 3x3 matrix

    I've done the problem but I just want to know if I'm on the right track because I've solved many others this way. In other words, is my answer correct?
    Determine for which values of c the following matrix is invertible :
    \left[ \begin{array}{ccc} 1 & c & -1 \\ c & 1 & 1 \\ 0 & 1 & c\end{array} \right].
    From my memory I think that this holds : A matrix A is invertible if and only if its determinant is different from 0. So I calculated the determinant of the matrix above to be -1-c^3, from which I concluded that the matrix is invertible \forall c \in \mathbb{C} such that c\neq -1.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Apr 2008
    Posts
    1,092
    You correctly calculated the determinant and your statement about the matrix's invertibility is true.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor arbolis's Avatar
    Joined
    Apr 2008
    From
    Teyateyaneng
    Posts
    1,000
    Awards
    1
    Quote Originally Posted by icemanfan View Post
    You correctly calculated the determinant and your statement about the matrix's invertibility is true.
    Youpi!!!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] Finding determinant of 4x4 matrix
    Posted in the Advanced Algebra Forum
    Replies: 2
    Last Post: February 8th 2010, 05:39 PM
  2. [SOLVED] determinant of a matrix.
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: October 21st 2009, 08:39 PM
  3. [SOLVED] matrix determinant
    Posted in the Advanced Algebra Forum
    Replies: 4
    Last Post: February 10th 2009, 11:12 AM
  4. [SOLVED] Finding a determinant (matrix)
    Posted in the Advanced Algebra Forum
    Replies: 2
    Last Post: September 16th 2008, 10:25 AM
  5. [SOLVED] Triangular matrix/determinant
    Posted in the Advanced Algebra Forum
    Replies: 8
    Last Post: September 16th 2008, 09:19 AM

Search Tags


/mathhelpforum @mathhelpforum