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frank0520
 one year ago
A=3 1 1
 1 3 1
1 1 3
Calculate A(A+5I) and use the result to find the inverse of A.
frank0520
 one year ago
A=3 1 1  1 3 1 1 1 3 Calculate A(A+5I) and use the result to find the inverse of A.

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frank0520
 one year ago
Best ResponseYou've already chosen the best response.1I got: 4 0 0  0 4 0 0 0 4 for the computation. And I got: 1/4 0 0  0 1/4 0 0 0 1/4 for the inverse. Is this the correct inverse?

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1I'm getting \[\Large A(A+5I) = \begin{bmatrix}4 & 0 & 0\\0 & 4 & 0\\0 & 0 & 4\\ \end{bmatrix}\] as well

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1I don't agree with your inverse though. I'm getting a different matrix for \(\Large A^{1}\)

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1To check, the product of \(\Large A\) and \(\Large A^{1}\) (in either order) should be equal to \[\Large I_3 = \begin{bmatrix}1 & 0 & 0\\0 & 1 & 0\\0 & 0 & 1\end{bmatrix}\]

frank0520
 one year ago
Best ResponseYou've already chosen the best response.1@jim_thompson5910 I did the inverse of the computation. I also did the inverse of just A and got: \[\left[\begin{matrix}1/2 & 1/4 & 1/4 \\ 1/4 & 1/2 & 1/4 \\ 1/4 & 1/4 & 1/2\end{matrix}\right]\] I did the product of \[A \ and\ A^1\] and got the \[I_3\] matrix.

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1You have the correct inverse

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1I'm not sure how `Calculate A(A+5I) and use the result to find the inverse of A.` fits into finding the inverse of A though

frank0520
 one year ago
Best ResponseYou've already chosen the best response.1@jim_thompson5910 Thanks for the help! I'm not sure either, maybe its just worded wrong.

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1you're welcome
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