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Mathematics
Mathematics
Problem
Show that
sin
47
∘
+
sin
61
∘
−
sin
11
∘
−
sin
25
∘
=
cos
7
∘
\sin 47^\circ + \sin 61^\circ - \sin 11^\circ - \sin 25^\circ = \cos 7^\circ
sin
4
7
∘
+
sin
6
1
∘
−
sin
1
1
∘
−
sin
2
5
∘
=
cos
7
∘
.
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