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Hi can someone please help me? If sin2A=cos 3A find the value of A. Can you please explain in full detail how you arrived at your answer? Also Find the exact value of (sec30)^2. Will I need to use a calculator in order to solve this prob?

1 Answer

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Sin (x) = Cos (90 - x)
sin(2A) = cos (90 - 2A)
=cos (3A)
90 - 2A = 3A
5A=90
A=18

User Delphian
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