Help with Matric proof!

  • Thread starter BigDave48
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  • #1
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Main Question or Discussion Point

Let A= I - X(X'X)inverseX' to clarify: '=transpose; inverse of quantity (X'X)

1. Must A be a square matrix?
2. Must (X'X) be a square matrix?
3. Must X be a square matrix?
4. Show whether matrix A is an idempotent matrix (i.e. that AA=A)

Thanks.
 

Answers and Replies

  • #2
mathwonk
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im so stupid! i cant follow aNY OF THAT. if i could understand the question i could answer it instantly.
 
  • #3
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Sorry. I really would appreciate some help.

To be more clear: I is an identity matrix

Questions 1,2,and 3 are essentially Yes/No with a provided proof or explanation.

Does this help, clarify?

Thanks.
 
  • #4
mathwonk
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come on man.
 
  • #5
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What do you mean by
"Let A= I - X(X'X)inverseX' to clarify: '=transpose; inverse of quantity (X'X)"

Sorry but it's incomprehensible.
 

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