Find Order of Subgroup of 4x4 Matrices in G

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SUMMARY

The order of the subgroup generated by the 4x4 matrix A, defined as | 0 1 0 0 |, | 0 0 0 1 |, | 0 0 1 0 |, | 1 0 0 0 |, is determined to be 3. This conclusion is reached by calculating A^3, which results in the identity matrix e, defined as | 1 0 0 0 |, | 0 1 0 0 |, | 0 0 1 0 |, | 0 0 0 1 |. The process involves multiplying the matrix A by itself three times to achieve the identity, confirming that the order of the subgroup is indeed 3.

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Homework Statement



Thus far in my studying I've been able to at least have a sense of where to start solving the problems... until now.

Find the order of the subgroup of the multiplicative group G of 4x4 matrice generated by:

| 0 1 0 0 |
| 0 0 0 1 |
| 0 0 1 0 |
| 1 0 0 0 |

Recall the identity e:

| 1 0 0 0 |
| 0 1 0 0 |
| 0 0 1 0 |
| 0 0 0 1 |

Homework Equations



The Attempt at a Solution



No clue, whatsoever. :(
 
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Call your matrix A. What's A3?
 
I'm not sure? =(
 
What do you mean, "I'm not sure"? Cube the matrix, i.e. multiply it by itself three times. Then you'll know what A^3 is. You aren't giving VKint the help deserved of the clue.
 
Ok, had to remember how to multiply matrices. I got the identity, e.
 
So did I. Problem solved, right?
 
I don't quite understand. So is the order 3 because that's how many times I had to multiply it by itself to get the identity?
 
A isn't the identity, A^2 isn't the identity, A^3 is. So yes, the order is 3. Look up 'order of a group element'.
 
Awesome, thanks.
 

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