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Question : 20 of 160
Marks:
+1,
-0
Solution:
sin‌20∘⋅sin‌40∘⋅sin‌60∘⋅sin‌80∘ =sin‌60∘⋅(‌‌sin(3×20∘)) =‌(sin‌60∘)2=‌×‌=‌ ‌‌(∵sin‌A‌sin(60∘−A)‌sin(60∘+A)=‌‌sin‌3‌A)
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