(cot‌α1)(cot‌α2)...(cot‌αn)=1 ⇒(cos‌α1)(cos‌α2)...(cos‌αn) =(sin‌α1)(sin‌α2)...(sin‌αn) .....(i) LHS and RHS will he maximum with equal values it α1=α2=...=αn=
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4
As, cos‌
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=sin‌
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⇒ Maximum value of (cos‌α1)(cos‌α2)...(cos‌αn)