1
NDA Mathematics 18 April 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language
If $\vec a, \vec b\:and \: \vec c$ are coplanar, then what is $(2\vec a\times 3\vec b)\cdot4\vec c+(5\vec b\times 3\vec c)\cdot6\vec a$ equal to?
A
114
B
66
C
0
D
-66
2
NDA Mathematics 18 April 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language

Consider the following statements:

1. The cross product of two unit vectors is always a unit vector.

2. The dot product of two unit vectors is always unity.

3. The magnitude of sum of two unit vectors is always greater than the magnitude of their difference.

Which of the above statements are not correct?

A
1 and 2 only
B
2 and 3 only
C
1 and 3 only
D
1, 2 and 3
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