Find A2 – 5A + 6I, if 
2
0
1
A
2
1
3
1
1
0




= 



−


16 If 
1
0
2
A
0
2
1
2
0
3




= 





, prove that A3 – 6A2 + 7A + 2I = 0
17 If 
3
2
1
0
A
and I=
4
2
0
1
−




= 



−




, find k so that A2 = kA – 2I
18 If 
0
tan 2
A
tan
0
2
α


−


= 

α






 and I is the identity matrix of order 2, show that
I + A = (I – A) 
cos
sin
sin
cos
α
−
α




α
α


19