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Which of the following is/are the value of `cos [(1)/(2) cos^(-1) (cos (-(14pi)/(5)))]` ?A. `cos(-(7pi)/(5))`B. `sin((pi)/(10))`C. `cos((2pi)/(5))`D. `-cos((3pi)/(5))`

Answer» Correct Answer - B::C::D
`cos (-(14pi)/(5)) = cos.(14pi)/(5) = cos.(4pi)/(5)`
Hence, `cos.(1)/(2) cos^(-1) (cos.(4pi)/(5)) = cos.(2pi)/(5)`


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