SOLUTION: Write appropriate relationships for sin(4A) and cos(4A) in terms of sin(A) and cos(A). Show your work.

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Question 1105258: Write appropriate relationships for sin(4A) and cos(4A) in terms of sin(A) and cos(A). Show your work.
Answer by Alan3354(69443) About Me  (Show Source):
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Write appropriate relationships for sin(4A) and cos(4A) in terms of sin(A) and cos(A).
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sin(4x) = 2sin(2x)cos(2x)
= 2sin(x)cos(x)*cos(2x)
= 2sin(x)cos(x)*(cos^2(x) - sin^2(x))
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cos(4x) = cos^2(2x) - sin^2(2x)
= (cos^2(x) - sin^2(x))^2 - (2sin(x)cos(x))^2