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Byju's Answer
Standard XII
Mathematics
Applications of Cross Product
If a× b =2i...
Question
If
a
×
b
=
2
i
+
2
j
−
k
,
a
+
b
=
i
−
3
j
−
4
k
then
A
a
=
1
4
i
+
1
4
j
+
k
;
b
=
3
4
i
−
13
4
j
−
5
k
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B
a
=
j
+
2
k
;
b
=
i
−
4
j
−
6
k
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C
a
=
−
1
4
i
+
7
4
j
+
2
k
;
b
=
5
4
i
−
19
4
j
−
7
k
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D
a
=
1
2
i
−
1
2
j
;
b
=
3
4
i
−
13
4
j
−
4
k
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Solution
The correct options are
A
a
=
1
4
i
+
1
4
j
+
k
;
b
=
3
4
i
−
13
4
j
−
5
k
B
a
=
j
+
2
k
;
b
=
i
−
4
j
−
6
k
D
a
=
−
1
4
i
+
7
4
j
+
2
k
;
b
=
5
4
i
−
19
4
j
−
7
k
Checking option (A)
→
a
=
1
4
^
i
+
1
4
^
j
+
^
k
→
b
=
3
4
^
i
−
13
4
^
j
−
5
^
k
→
a
+
→
b
=
1
4
^
i
+
1
4
^
j
+
^
k
+
3
4
^
i
−
13
4
^
j
−
5
^
k
^
i
−
3
^
j
−
4
^
k
=
^
i
−
3
^
j
−
4
^
k
valid option
Now for option (B)
→
a
=
^
j
+
2
^
k
→
b
=
^
i
−
4
^
j
−
6
^
k
→
a
+
→
b
=
^
j
+
2
^
k
+
^
i
−
4
^
j
−
6
^
k
^
i
−
3
^
j
−
4
^
k
=
^
i
−
3
^
j
−
4
^
k
valid option
Now for option (c) is wrong correct
→
b
=
5
4
^
i
−
19
4
^
j
−
6
^
k
→
a
=
−
1
4
^
i
+
7
4
^
j
+
2
^
k
→
b
=
5
4
^
i
−
19
4
^
j
−
6
^
k
→
a
+
→
b
=
−
1
4
^
i
+
7
4
^
j
+
2
^
k
+
5
4
^
i
−
19
4
^
j
−
6
^
k
^
i
−
3
^
j
−
4
^
k
=
^
i
−
3
^
j
−
4
^
k
valid option
Now for option (D)
→
a
=
1
2
^
i
+
1
2
^
j
→
b
=
3
4
^
i
−
13
4
^
j
−
4
^
k
→
a
+
→
b
=
1
2
^
i
+
1
2
^
j
+
3
4
^
i
−
13
4
^
j
−
4
^
k
5
4
^
i
−
11
4
^
j
−
4
^
k
≠
^
i
−
3
^
j
−
4
^
k
not valid option
Suggest Corrections
0
Similar questions
Q.
Find
a
→
·
b
→
when
(i)
a
→
=
i
^
-
2
j
^
+
k
^
and
b
→
=
4
i
^
-
4
j
^
+
7
k
^
(ii)
a
→
=
j
^
+
2
k
^
and
b
→
=
2
i
^
+
k
^
(iii)
a
→
=
j
^
-
k
^
and
b
→
=
2
i
^
+
3
j
^
-
2
k
^
Q.
Find the angle between the vectors
a
→
and
b
→
, where
(i)
a
→
=
i
^
-
j
^
and
b
→
=
j
^
+
k
^
(ii)
a
→
=
3
i
^
-
2
j
^
-
6
k
^
and
b
→
=
4
i
^
-
j
^
+
8
k
^
(iii)
a
→
=
2
i
^
-
j
^
+
2
k
^
and
b
→
=
4
i
^
+
4
j
^
-
2
k
^
(iv)
a
→
=
2
i
^
-
3
j
^
+
k
^
and
b
→
=
i
^
+
j
^
-
2
k
^
(v)
a
→
=
i
^
+
2
j
^
-
k
^
,
b
→
=
i
^
-
j
^
+
k
^
Q.
Show the each of the following triads of vectors are coplanar:
(i)
a
→
=
i
^
+
2
j
^
-
k
^
,
b
→
=
3
i
^
+
2
j
^
+
7
k
^
,
c
→
=
5
i
^
+
6
j
^
+
5
k
^
(ii)
a
→
=
-
4
i
^
-
6
j
^
-
2
k
^
,
b
→
=
-
i
^
+
4
j
^
+
3
k
^
,
c
→
=
-
8
i
^
-
j
^
+
3
k
^
(iii)
a
^
=
i
^
-
2
j
^
+
3
k
^
,
b
^
=
-
2
i
^
+
3
j
^
-
4
k
^
,
c
^
=
i
^
-
3
j
^
+
5
k
^
Q.
The point having position vectors 2i + 3j + 4k, 3i + 4j + 2k, 4i + 2j + 3k are the vertices of.
Q.
The unit vector in the direction of sum of the vectors
→
A
=
2
ˆ
i
+
4
ˆ
j
−
7
ˆ
k
and
→
B
=
4
ˆ
i
−
6
ˆ
j
+
4
ˆ
k
will be