Tardigrade
Tardigrade - CET NEET JEE Exam App
Exams
Login
Signup
Tardigrade
Question
Mathematics
If A=[ beginmatrix 2 -1 1 2 endmatrix ], then A2+2A-3I=
Q. If
A
=
[
2
1
−
1
2
]
,
then
A
2
+
2
A
−
3
I
=
3542
177
J & K CET
J & K CET 2014
Matrices
Report Error
A
[
4
6
−
6
4
]
59%
B
0
12%
C
[
−
6
−
2
2
6
]
15%
D
5
I
14%
Solution:
Given,
A
=
[
2
1
−
1
2
]
Now,
A
2
=
[
2
1
−
1
2
]
[
2
1
−
1
2
]
=
[
4
−
1
2
+
2
−
2
−
2
−
1
+
4
]
⇒
A
2
=
[
3
4
−
4
3
]
Now,
A
2
+
2
A
−
3
l
=
[
3
4
−
4
3
]
+
2
[
2
1
−
1
2
]
−
3
[
1
0
0
1
]
=
[
3
+
4
−
3
−
4
−
2
−
0
4
+
2
−
0
3
+
4
−
3
]
=
[
4
6
−
6
4
]