Suppose that: E_4 [[1,3,4],[2,2,3],[-5,4,4]] = [[1,3,4],[8,8,12],[-5,4,4]] Find E_4 and (E_4)^-1

Asked on

1 Answer | Add Yours

mathsworkmusic's profile pic

Posted on (Answer #1)

`E_4` is an elementary matrix. That is, one that can be reached from the identity matrix of the same dimension by an elementary operation.

In this case the operation is multiplying row 2 by 4.

Therefore `E_4 = ((1,0,0),(0,4,0),(0,0,1))`

`E_4^(-1)`  is also an elementary matrix and is simply the inverse operation, ie dividing row 2 by 4. So that

`E_4^(-1) = ((1,0,0),(0,1/4,0),(0,0,1))`


We’ve answered 397,417 questions. We can answer yours, too.

Ask a question