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

suju101 Group Title

1 2 3 4 5 6 7 8 9 | what is the minor of a22??

  • 2 years ago
  • 2 years ago

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

    If I'm correct about what a minor is, the minor of \(A_{22}\) would be the determinant of the matrix if you removed the second row and second column. In other words, the minor of \(A_{22}\) would then be \[(1*9)-(3*7) = 9-21=-12\]

    • 2 years ago
  2. suju101 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    are minor and cofactor same thing??

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

    Close, but not quite. To get the cofactor, you would then have to multiply your minor by \((-1)^{i+j}\) where \(i, j\) are the indices of the row and column you're removing. In your case, they're both 2, so the cofactor would be \[(-1)^{2+2} * (-12) = (-1)^4 *(-12) = 1*(-12)=-12\]which is indeed the minor, but this is not always the case.

    • 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.