The value of 36(4 cos 2 9° - 1) (4 cos 2 27° - 1) (4 cos 2 81° - 1) (4 cos 2 243° - 1) is
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We need to find the value
36(4 cos 2 9° - 1) (4 cos 2 27° - 1) (4 cos 2 81° - 1) (4 cos 2 243° - 1)
= 36[(4 cos 2 9° - 1) (4 sin 2 9° - l) (4 cos 2 27° - l) (4 sin 2 27° - l)]
= 36[(4(2 cos 9° sin9°) 2 - 4cos 2 9° -4sin 2 9° + l] (4(2 sin27° cos 9°) 2 -4cos 2 27° -4sin 2 27° + l)]
= 36 [(4 sin 2 18° - 4 + l) (4 sin 2 54° - 4 + l)]
= 36[(4 sin 2 18° - 3) (4 sin 2 54° - 3)]



Hence this is the correct option.
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