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Byju's Answer
Standard XII
Mathematics
Equal Vectors
Find the cros...
Question
Find the cross products of the vectors
1.
a
=
i
−
2
j
+
3
k
,
b
=
3
i
−
6
j
+
9
k
2.
a
=
−
2
i
−
4
k
,
b
=
i
−
2
j
−
k
,
c
=
i
−
4
j
+
3
k
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Solution
1
→
a
=
^
i
−
2
^
j
+
3
^
k
→
b
=
3
^
i
−
6
^
j
+
9
^
k
→
a
×
→
b
=
⎡
⎢
⎣
^
i
^
j
^
k
1
−
2
3
3
−
6
9
⎤
⎥
⎦
=
^
i
(
−
18
+
18
)
−
^
j
(
9
−
9
)
+
^
k
(
−
6
+
6
)
=
0
∴
→
a
×
→
b
=
0
2
→
a
=
−
2
^
i
−
4
^
k
→
b
=
^
i
−
2
^
j
−
^
k
→
c
=
^
i
−
4
^
j
+
3
^
k
→
a
×
(
→
b
×
→
c
)
=
(
→
a
.
→
c
)
→
b
−
(
→
a
.
→
b
)
→
c
=
(
(
−
2
^
i
−
4
^
k
.
(
^
i
−
4
^
j
+
3
^
k
)
)
)
(
^
i
−
2
^
j
−
^
k
)
=
(
(
2
^
i
−
4
^
k
)
.
(
^
i
−
2
^
j
−
^
k
)
)
(
^
i
−
4
^
j
+
3
^
k
)
=
(
−
2
+
0
−
12
)
(
^
i
−
2
^
j
−
^
k
)
−
(
−
2
+
4
)
(
^
i
−
4
^
j
+
3
^
k
)
=
−
14
(
^
i
−
2
^
j
−
^
k
)
−
2
(
^
i
−
4
j
+
3
^
k
)
=
−
14
^
i
+
28
^
j
+
14
^
k
−
2
^
i
+
8
^
j
−
6
^
k
=
−
16
^
i
+
36
^
j
+
8
^
k
Suggest Corrections
0
Similar questions
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 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