Question

Cos 24° + cos 5° + Cos 175° + cos 204
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Answer 1

Answer:

Cos(24°) + cos(5°) + cos (175°) + cos (204°) + cos (300°)

= Cos(24°) + cos(5°) + cos (180° - 5°) + cos (180° + 24°) + cos (360° - 60°)

we know cos (180° +x ) = - cos x & cos (180° -x ) = - cos x & cos (360° - x) = cos x

so using

= Cos(24°) + cos(5°) - cos ( 5°) - cos ( 24°) + cos ( 60°)

= cos (60° )

= 1/2