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Question : 21 of 160
Marks:
+1,
-0
Solution:
(4cos29∘−3)(4cos227∘−3) =‌(4cos39∘−3‌cos‌9∘)×‌(4cos327∘−3‌cos‌27∘) ‌=‌(cos‌27∘)×‌(cos‌81∘)‌=‌| cos(90∘−9∘) |
| cos‌9∘ |
=‌=tan‌9∘
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