Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Linear transformation

  1. Feb 13, 2012 #1
    Why would you want to use a matrix for a linear transformation?
    Why not just use the given transformation instead of writing it as a matrix?
  2. jcsd
  3. Feb 13, 2012 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    If you have a number of rotations to be performed in succession, you can just multiply the matrices. Also you can determine information about a rotation, for example the axis of rotation, by calclulating the eigevectors of the matrix.
  4. Feb 13, 2012 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    Using the transformation or using the matrix is equivalent. You won't lose information if you use the matrix.

    If you want to keep on using the transformation, then you can do this. But in many cases, using the matrix is simply much easier. Finding eigenvalues for example is much easier with a matrix than with a transformation.
  5. Feb 15, 2012 #4


    User Avatar
    Science Advisor

    one reason is:

    a matrix calculation reduces the computation of composition of linear transformations, as well as the computation of image elements under a linear transformation, to arithmatic operations in the underlying field. that is:


    sometimes, this is preferrable for getting "actual answers" in a physical application, where some preferred basis (coordinate system) might already be supplied.

    for example, the differentiation operator is a linear transformation from Pn(F) to Pn(F).

    actually "computing a derivative" IS just computing the matrix product [D]B[p]B = [p']B:

    for n = 2, and F = R, we have for the basis B = {1,x,x2}, that [D]B=

    [0 1 0]
    [0 0 2]
    [0 0 0],

    or that if p(x) = a + bx + cx2,

    p'(x) = b + 2cx.

    of course, this would be just as easy using D(p) = p' using the calculus definition,

    but it's not so clear what happens if you want to use THIS basis: {1+x,1-x,1-x2}, using the calculus definition, whereas the matrix form makes it transparent.
  6. Feb 18, 2012 #5
    Is it by using a matrix representation of a derivative that CAS and programmable calculators evaluate derivatives?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Linear transformation
  1. Linear Transformation (Replies: 3)

  2. Linear Transformations (Replies: 2)

  3. Linear transformation (Replies: 4)

  4. Linear transformations (Replies: 6)

  5. Linear transformation (Replies: 5)