Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

john123456789 Group Title

A*B*(C^T) *D*B*(A^T) = A*(B^T) Assuming that all matrices are n × n invertible, solve for D

  • 2 years ago
  • 2 years ago

  • This Question is Closed
  1. vf321 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    \[ABC^TDBA^T = AB^T\]\[(AB)^{-1}ABC^TDBA^T =(AB)^{-1} AB^T\]\[I_nC^TDBA^T =(AB)^{-1} AB^T\]\[C^TDBA^T (DBA^T)^{-1}=(AB)^{-1} AB^T(DBA^T)^{-1}\]\[C^T=((AB)^{-1} AB^T(DBA^T)^{-1})\]\[C=(B^{-1}A^{-1}AB^T(A^T)^{-1}B^{-1}D^{-1})^T\]\[C=(B^{-1}I_nB^T(A^T)^{-1}B^{-1}D^{-1})^T\]\[C=(D^T)^{-1}(B^T)^{-1}A^{-1}B(B^T)^{-1}\]

    • 2 years ago
  2. john123456789 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    this is solve for C my question was to solve for D

    • 2 years ago
  3. vf321 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Lol whoops do you see what I did at least? Try to replicate it, I don't have time to re-do this. If no one answers this question next time I check (may be a couple days), then I'll answer it.

    • 2 years ago
  4. john123456789 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    yeah, but on the 3 line there IC^T...and on the four the I is gone why is that ?

    • 2 years ago
  5. vf321 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    I is the identity matrix, any matrix Q like so makes I: \[QQ^{-1}=I\]In the spot you're looking at Q=AB. Also, I follows the following property: \[AI=IA=A\] for any A

    • 2 years ago
  6. john123456789 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    ok so once your albe to reduce to I you can just remove it for the equation

    • 2 years ago
  7. vf321 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    yes

    • 2 years ago
    • Attachments:

See more questions >>>

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.