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Mathematics
Mathematics
Problem
If
a
⃗
\vec{a}
a
,
b
⃗
\vec{b}
b
,
c
⃗
\vec{c}
c
are three mutually perpendicular unit vectors. If
θ
\theta
θ
is the angle between
a
⃗
\vec{a}
a
and
2
a
⃗
+
3
b
⃗
+
6
c
⃗
2\vec{a} + 3\vec{b} + 6\vec{c}
2
a
+
3
b
+
6
c
, find the value of
cos
θ
\cos \theta
cos
θ
.
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