1
NDA Mathematics 18 April 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language
If A and B are square matrices of order 2 such that det(AB) = det(BA), then which one of the following is correct?
A
A must be a unit matrix.
B
B must be a unit matrix.
C
Both A and B must be unit matrices.
D
A and B need not be unit matrices.
2
NDA Mathematics 18 April 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language

What is cot 2x cot 4x - cot 4x cot 6x - cot 6x cot 2x equal to

A
-1
B
0
C
1
D
2
3
NDA Mathematics 18 April 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language
If M is the mean of n observations x1 - k, x2 - k, x3 - k, _ _ _, xn - k, where k is any real number, then what is the mean of x1, x2, x3, _ _ _, xn?
A
M
B
M + k
C
M - k
D
kM
4
NDA Mathematics 18 April 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language
What is the sum of deviations of the variate values 73, 85, 92, 105, 120 from their mean?
A
-2
B
-1
C
0
D
5
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