Question:
If A = 122 212 221 then what is A2 – 4A equal to?
If A = 122 212 221 then what is A2 – 4A equal to?
Options:
- a) -5I3
- b) -I3
- c) I3
- d) 5I3 Where I3 is the identity matrix of order 3.
- a) -5I3
- b) -I3
- c) I3
- d) 5I3 Where I3 is the identity matrix of order 3.
correct answer : d)
Explanation:
A2 =
122
212
221
122
212
221
=
988
898
889
A2 – 4A =
988
898
889
–
488
848
884
=
50 0
05 0
00 5
= 5I3
A2 =
122
212
221
122
212
221
=
988
898
889
A2 – 4A =
988
898
889
–
488
848
884
=
50 0
05 0
00 5
= 5I3