SOLUTION: This is the questions i'm sorry i cannot upload it http://i67.tinypic.com/i39lqq.png I found that a = 1/sqrt(2) but I have problem on 2nd and 3rd questions. How can I find s

2.  Answer.  n = 6.

    You can easily check it directly on your own:   =  = .



3.  You have   = -I.

    Then  = I.

    It means that every 8-th degree of A will be equal to I.


    It also means that the sequence of i-th degrees is cyclical/periodical with the period of 8:

    n        1    2    3    4    5    6    7    8    9    10

   :      A        -I   -A       I    A      . . . periodical with the period 8 . . .