A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

I wonder if the Prof is correct in Lecture 2 at minute 8:19 where he said that the 3rd pivot is 5. I think that it is -3

  • This Question is Open
  1. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    The matrix after the first step of elimination looks like: \[\left[\begin{matrix}1 & 2 & 1\\ 0 & 2 & -2\\ 0 & 4 & 1\end{matrix}\right]\] We want to eliminate element 32 (that is 4). To do that, we multiply second row by 2 (to get 4 in 22 position): \[\left[\begin{matrix}1 & 2 & 1\\ 0 & 4 & -4\\ 0 & 4 & 1\end{matrix}\right]\] Finally, we subtract second line from the third: \[\left[\begin{matrix}1 & 2 & 1\\ 0 & 2 & -2\\ 0-0 & 4-4 & 1-(-4)\end{matrix}\right] =\left[\begin{matrix}1 & 2 & 1\\ 0 & 2 & -2\\ 0& 0& 5\end{matrix}\right]. \]

  2. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

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.