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NDA Math Vector Algebra
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© examsnet.com
Question : 34
Total: 101
If the position vectors of points A and B are 3
^
i
− 2
^
j
+
^
k
and 2
^
i
+ 4
^
j
-3
^
k
respectively, then what is the length of
→
A
B
?
[NDA I 2019]
√
14
√
29
√
43
√
53
Validate
Solution:
(D)
Given position vector of A and B are
→
O
A
=
3
^
i
−
2
^
j
+
^
k
→
O
B
=
2
^
i
+
4
^
j
−
3
^
k
∴
→
A
B
=
→
O
B
−
→
O
A
=
(
2
^
i
+
4
^
j
−
3
^
k
)
−
(
3
^
i
−
2
^
j
+
^
k
)
= −
^
i
+
6
^
j
+
4
^
k
∴ length of
→
A
B
=
√
(
−
1
)
2
+
(
6
)
2
+
(
−
4
)
2
=
√
1
+
36
+
16
=
√
53
© examsnet.com
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