Results 1 to 5 of 5

Math Help - Matrix Problem

  1. #1
    Newbie
    Joined
    Jul 2009
    Posts
    1

    Matrix Problem

    The square matrix X is such that X^3 = 0. Show that the inverse of the matrix (I - X) is I + X + X^2.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member Random Variable's Avatar
    Joined
    May 2009
    Posts
    959
    Thanks
    3
     (i-x)(i+x+x^{2}) = i^{2} + ix +ix^{2} - xi -x^{2} - x^{3}

     = i + x + x^{2} - x - x^{2} - x^{3} =  i - 0 =  i

    EDIT : I don't why it keeps making it lowercase.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member Random Variable's Avatar
    Joined
    May 2009
    Posts
    959
    Thanks
    3
    You should probably also show that (I+X+X^2)(I-X) = I
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,788
    Thanks
    1683
    Awards
    1
    Quote Originally Posted by Random Variable View Post
    EDIT : I don't why it keeps making it lowercase.
    Type [tex]\mathcal{X}[/tex] to get \mathcal{X} .
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Super Member Random Variable's Avatar
    Joined
    May 2009
    Posts
    959
    Thanks
    3
    Quote Originally Posted by Plato View Post
    Type [tex]\mathcal{X}[/tex] to get \mathcal{X} .
    Why is it converted to lowercase sometimes?

    I guess I could also use  \text{X}
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 0
    Last Post: December 2nd 2010, 03:40 PM
  2. Matrix Problem
    Posted in the Algebra Forum
    Replies: 2
    Last Post: February 22nd 2010, 11:26 PM
  3. matrix problem
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 18th 2008, 10:46 AM
  4. Help with Matrix Problem
    Posted in the Pre-Calculus Forum
    Replies: 0
    Last Post: October 26th 2008, 05:57 PM
  5. Another matrix problem
    Posted in the Algebra Forum
    Replies: 2
    Last Post: June 27th 2007, 08:36 AM

Search Tags


/mathhelpforum @mathhelpforum