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 on linear algebra(also Matlab related)

  1. Jun 23, 2014 #1
    Hi, Can someone explain me the division operation in the picture. First for left division we use (.\ ) not only ( \ ) And it is strange that when we divide first column of A by first column of B( here first column of B is 44) how can we find -5.1250 ?
     

    Attached Files:

    Last edited: Jun 23, 2014
  2. jcsd
  3. Jun 23, 2014 #2

    micromass

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor
    2016 Award

  4. Jun 23, 2014 #3
  5. Jun 23, 2014 #4

    MarneMath

    User Avatar
    Education Advisor

    That just happens to be what matlab calls the method that solves the linear system. A person could also write it as mldivide(A,b). Also, in matlab A.\B nd A\B are equivalent statements. Try it out.
     
  6. Jun 26, 2014 #5

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    That's NOT standard notation. If Ax= b (and A is invertible) then [itex]x= A^{-1}b[/itex]. if xA= b then [itex]x= bA^{-1}[/itex]. Because standard division (a/b) does not distinguish between "divide on the left" and "divide on the right" we don't normally use that notation.

    That particular author (and possibly math lab- I don't use it) is using a special notation to distinguish between "division on the left" ([itex]A^{-1}b[/itex]) and "division on the right" ([itex]bA^{-1}[/itex]).
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: A question on linear algebra(also Matlab related)
Loading...