1
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language
If the number of selections of r as well as things from 5n different things are equal, then what is the value of r?
A
n
B
2n
C
3n
D
4n
2
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language
What is the number of selections of at most 3 things from 6 different things?
A
20
B
22
C
41
D
42
3
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language

If $A=\begin{bmatrix}x&y&z\\y&z&x\\z&x&y\end{bmatrix}$

where x,y,z are integers, is an orthogonal matrix, then what is A2 equal to?

A
Null matrix 
B
Identity matrix
C
A
D
-A
4
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language
Consider the following for the three (03) items that follow: Let , and
What is  equal to?
A
-1
B
0
C
2sin5
D
2cos5
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