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Question : 193 of 200
Marks:
+1,
-0
Solution:
‌cos276∘+cos216∘−cos‌76∘‌cos‌16∘‌=cos276∘+1−sin‌216∘−‌⋅2‌cos‌76∘‌cos‌16∘‌=1+cos(76∘+16∘)‌cos(76∘−16∘)‌‌‌‌‌‌‌−‌(cos‌92∘+cos‌60∘)‌=1+‌‌cos‌92∘−‌‌cos‌92∘−‌‌=1−‌=‌
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