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Byju's Answer
Standard XII
Mathematics
Applications of Dot Product
Find the proj...
Question
Find the projection of the vector
i
−
2
j
+
k
on the vector
4
i
−
4
j
+
7
k
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Solution
Let
→
a
=
i
−
2
j
+
k
and
→
b
=
4
i
−
4
j
+
7
k
Now
→
a
⋅
→
b
=
(
^
i
−
2
^
j
+
^
k
)
(
4
^
i
−
4
^
j
+
7
^
k
)
⇒
→
a
.
→
b
=
4
+
8
+
7
=
19
Also,
|
→
a
|
=
√
1
+
4
+
1
=
√
6
,
|
→
b
|
=
√
16
+
16
+
49
=
√
81
=
9
Therefore projection of
→
a
on
→
b
is
=
|
→
a
⋅
→
b
|
|
→
b
|
=
19
9
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