Let A be an m n matrix with rank r. Suppose A = BU, where U is in echelon form. Show

Chapter 3, Problem 13

(choose chapter or problem)

Get Unlimited Answers
QUESTION:

Let A be an m n matrix with rank r. Suppose A = BU, where U is in echelon form. Show that the first r columns of B give a basis for C(A). (In particular, if EA = U, where U is the echelon form of A and E is the product of elementary matrices by which we reduce A to U, then the first r columns of E 1 give a basis for C(A).)

Questions & Answers

QUESTION:

Let A be an m n matrix with rank r. Suppose A = BU, where U is in echelon form. Show that the first r columns of B give a basis for C(A). (In particular, if EA = U, where U is the echelon form of A and E is the product of elementary matrices by which we reduce A to U, then the first r columns of E 1 give a basis for C(A).)

ANSWER:

Step 1 of 2

It is given that, is an  matrix with rank .

And,

.

Also, is in echelon form.

It is known that,

If  be a -dimensional subspace.  Then any  vectors that span  must be linearly independent and any  linearly independent vectors in  must span .  

To prove that, the first  columns of  give a basis for .

Add to cart


Study Tools You Might Need

Not The Solution You Need? Search for Your Answer Here:

×

Login

Login or Sign up for access to all of our study tools and educational content!

Forgot password?
Register Now

×

Register

Sign up for access to all content on our site!

Or login if you already have an account

×

Reset password

If you have an active account we’ll send you an e-mail for password recovery

Or login if you have your password back