1
WB JEE 2009
MCQ (Single Correct Answer)
+1
-0.25

If A and B are square matrices of the same order and AB = 3I, then A$$-$$1 is equal to

A
3B
B
$${1 \over 3}$$B
C
3B$$-$$1
D
$${1 \over 3}$$B$$-$$1
2
WB JEE 2010
MCQ (Single Correct Answer)
+1
-0.25

If the matrices $$A = \left[ {\matrix{ 2 & 1 & 3 \cr 4 & 1 & 0 \cr } } \right]$$ and $$B = \left[ {\matrix{ 1 & { - 1} \cr 0 & 2 \cr 5 & 0 \cr } } \right]$$, then AB will be

A
$$\left[ {\matrix{ {17} & 0 \cr 4 & { - 2} \cr } } \right]$$
B
$$\left[ {\matrix{ 4 & 0 \cr 0 & 4 \cr } } \right]$$
C
$$\left[ {\matrix{ {17} & 4 \cr 0 & { - 2} \cr } } \right]$$
D
$$\left[ {\matrix{ 0 & 0 \cr 0 & 0 \cr } } \right]$$
3
WB JEE 2010
MCQ (Single Correct Answer)
+1
-0.25

If $$\omega$$ is an imaginary cube root of unity and $$\left| {\matrix{ {x + {\omega ^2}} & \omega & 1 \cr \omega & {{\omega ^2}} & {1 + x} \cr 1 & {x + \omega } & {{\omega ^2}} \cr } } \right| = 0$$, then one of the values of x is

A
1
B
0
C
$$-$$1
D
2
4
WB JEE 2010
MCQ (Single Correct Answer)
+1
-0.25

If $$A = \left[ {\matrix{ 1 & 2 \cr { - 4} & { - 1} \cr } } \right]$$ then A$$-$$1 is

A
$${1 \over 7}\left[ {\matrix{ { - 1} & 2 \cr 4 & 1 \cr } } \right]$$
B
$${1 \over 7}\left[ {\matrix{ 1 & 2 \cr { - 4} & { - 1} \cr } } \right]$$
C
$${1 \over 7}\left[ {\matrix{ { - 1} & { - 2} \cr 4 & 1 \cr } } \right]$$
D
Does not exist
WB JEE Subjects
EXAM MAP
Medical
NEET
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
CBSE
Class 12