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Question : 20 of 160
Marks:
+1,
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Solution:
Consider the expression.
(1+cos‌)(1+cos‌)(1+cos‌)(1+cos‌) ‌ Let ‌x=(1+cos‌)(1+cos‌)(1+cos‌)(1+cos‌) It is solved as,
x‌‌=(1+cos‌)(1+cos‌)(1+cos‌)(1+cos‌) x‌‌=(1+cos‌)(1+cos‌)(1−cos‌)(1−cos‌) ‌‌=(1−cos2‌)(1−cos2‌) ‌‌=(sin2‌)(sin2‌) Solve further,
x=sin2(‌)sin2(‌−‌) =sin2(‌)cos2(‌) =‌(2‌sin‌‌cos‌)2 =‌sin2‌ Solve further
x‌‌=‌×‌ ‌‌=‌
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