1. Not finding help here? Sign up for a free 30min 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!

A question in finding a invert of a certain operator

  1. Mar 8, 2008 #1
  2. jcsd
  3. Mar 8, 2008 #2

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    You are given that A2- A+ I= 0. Just basic algebra tells you that is the same as I= A- A2= A(I- A). Now, stop worrying about formulas, etc. and think about what A-1 means.
     
  4. Mar 8, 2008 #3
    it means that if we take the image of a certain basis
    and put it into the A^-1 we get the original basis

    how its gonna help me??

    thought of certain solution of making some basic multiplication
    operations

    i got the resolt

    A^-1=I-A
    is it ok??
     
    Last edited: Mar 8, 2008
  5. Mar 8, 2008 #4

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    ?? No, A-1 doesn't mean anything like that: it means the linear operation that "undoes" A. A-1Ax= x and AA-1x= x.

    My point was that A(I- A)= I shows that I -A does exactly what we want of the inverse: AA-1= I. Since A(I-A)= I, (and inverses are unique), A-1= I- A.
     
  6. Mar 8, 2008 #5
    so what is the answer??
    what is the value of A^-1
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: A question in finding a invert of a certain operator
Loading...