A = 2î + 3j + k
B = î + 2j- 2k
what is
1 A.B
2 A*B
Answers
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0
Answer:
Let a=
i
^
+
j
^
+
k
^
and b=2
i
^
−2
j
^
+2
k
^
and angle between them be θ
Then, cosθ=
∣a∣∣b∣
a⋅b
=
(1)
2
+(1)
2
+(1)
2
(2)
2
+(−2)
2
+(2)
2
(
i
^
+
j
^
+
k
^
)⋅(2
i
^
−2
j
^
+2
k
^
)
=
3
12
2−2+2
=
6
2
=
3
1
⇒θ=cos
−1
(
3
1
)
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