Which expression is equal to ?
sin
i
4
pi
5
i
cos
i
pi
10
i
+
cos
i
4
pi
5
i
sin
i
pi
10
i
sin
i
7
pi
10
i
sin
i
9
pi
10
i
cos
i
9
pi
10
i
cos
i
7
pi
10
i
ref_doc_title.
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