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Suppose we have  given matrix A = [[-2,1],[-1,4]]  determine the following elementary...

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hockeyfan54 | Student | Salutatorian

Posted April 23, 2013 at 9:49 PM via web

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Suppose we have  given matrix

A = [[-2,1],[-1,4]]

 determine the following elementary matrix and their inverse.

The elementary matrix E_1  multiplies the first row of A by 1/6. What is E_1 and (E_1)^-1 ?

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pramodpandey | College Teacher | Valedictorian

Posted April 24, 2013 at 8:59 AM (Answer #1)

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`A=[[-2,1],[-1,4]]`

`E_1: [[-2/6,1/6],[-1,4]]`

`` `|E_1|=-8/6+1/6=-7/6`

`E^(-1)_1=(1/(-7/6))[[4,-1/6],[1,-2/6]]`

`E^(-1)=[[-24/7,1/7],[-6/7,2/7]]`

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