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 A trust fund has ` 30,000 that must be invested in two different types of bonds The first bond pays 5% interest per year, and the second bond pays 7% interest
per year