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Mathematics
Problem
Let
a
=
i
^
\mathbf{a} = \hat{i}
a
=
i
^
be a vector which makes an angle of
120
∘
120^\circ
12
0
∘
with a unit vector
b
\mathbf{b}
b
. Then, the unit vector
(
a
+
b
)
(\mathbf{a} + \mathbf{b})
(
a
+
b
)
is a.
−
1
2
i
^
+
3
2
j
^
-\frac{1}{2}\hat{i} + \frac{\sqrt{3}}{2}\hat{j}
−
2
1
i
^
+
2
3
j
^
b.
−
3
2
i
^
+
1
2
j
^
-\frac{\sqrt{3}}{2}\hat{i} + \frac{1}{2}\hat{j}
−
2
3
i
^
+
2
1
j
^
c.
1
2
i
^
+
3
2
j
^
\frac{1}{2}\hat{i} + \frac{\sqrt{3}}{2}\hat{j}
2
1
i
^
+
2
3
j
^
d.
3
2
i
^
−
1
2
j
^
\frac{\sqrt{3}}{2}\hat{i} - \frac{1}{2}\hat{j}
2
3
i
^
−
2
1
j
^
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