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Mathematics
Problem
The value of
cos
12
∘
+
cos
84
∘
+
cos
156
∘
+
cos
132
∘
\cos 12^\circ + \cos 84^\circ + \cos 156^\circ + \cos 132^\circ
cos
1
2
∘
+
cos
8
4
∘
+
cos
15
6
∘
+
cos
13
2
∘
is: (a)
1
8
\frac{1}{8}
8
1
(b)
−
1
2
-\frac{1}{2}
−
2
1
(c) 1 (d)
1
2
\frac{1}{2}
2
1
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