Saturday

April 19, 2014

April 19, 2014

Posted by **Lisa** on Wednesday, September 8, 2010 at 4:18am.

predicted B=A(A'A)^(-1)A'B

why is the matrix C=A(A'A)^(-1)A' an idempotent and symmetric matrix? and is this matrix invertible?

- MATHS----Matrix -
**MathMate**, Wednesday, September 8, 2010 at 11:26amAssuming (A'A) is invertible, then (A'A)

^{-1}exists.

A(A'A)^{-1}A'

By the property of inverse of product of matrices,

(A'A)^{-1}

=A^{-1}A'^{-1}

Therefore

C=A(A'A)^{-1}A'

=A(A^{-1}A'^{-1})A'

=(A A^{-1}) (A'^{-1}A')

= (I) (I)

=I

after application of associativity and the properties of inverse of matrices.

Since I is idempotent and invertible, so is C.

- Equation of parabola -
**Bayarbold**, Friday, June 10, 2011 at 11:10amThe equation of the parabola which contains 2 points (1,1) and (-2,-2) and whose tangent at the point (1,1) has the slope k is y=1/3(A)x^2+1/3(B)x-2/3(C) Express A,B and C with k.Please solve this problem.please

**Related Questions**

Math - Mark each of the following True or False. ___ a. All vectors in an ...

math - This is a matrix question. R is the matrix (3r 1) (s 2s) 1. State, in ...

math - This is a matrix question. R is the matrix (3r 1) (s 2s) 1. State, in ...

linear algebra - 3. Suppose A is symmetric positive definite and Q is an ...

Math - Fine the size of the following matrix and its additive inverse matrix. ...

algebra - Hi guys: Can any one please tell me what does this means? Thanks...

Maths: Algebra Matrices Class 12th - matrix{{0, 1, -1}, {2, 1, 3}, {1, 1, 1}} ...

Calc - A video games shop is analyzing its sales performance using matrices. ...

linear algebra - 1)If A is an invertible matrix and k is a positive integer, ...

Algebra-Matrix - How would I do these Matrices? 1. |1/2 14 10 -8| 2, Let matrix ...