I need to find all 2x2 matrices A,

(a b)

(c d)

such that A^2=I2, the 2x2 identity matrix.

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- February 19th 2009, 07:26 PMSnooks02Matrices which are their own inverses
I need to find all 2x2 matrices A,

(a b)

(c d)

such that A^2=I2, the 2x2 identity matrix. - February 19th 2009, 10:15 PMtah
this means that A is equal to its inverse. So you may write the expression of and deduce 4 equations from the identification of it with A. It remains to solve these equations

- February 19th 2009, 10:57 PMJhevon
- February 19th 2009, 11:51 PMmath2009