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Question
Evaluate `cos[cos^-1 ((-sqrt(3))/2) + pi/6]`
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Solution
`cos[cos^-1 ((-sqrt(3))/2) + pi/6] = cos[cos^-1(cos (5pi)/6) + pi/6]` ......`(because cos (5pi)/6 = (-sqrt(3))/2)`
= `cos((5pi)/6 + pi/6)` ......`(because cos^-1 cosx = x; x ∈ [0, pi])`
= `cos(pi)` = –1
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