SOLUTION: Determine cos2x if sin^4 x = 25/36, the solution is in the first quadrant.

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Question 1063498: Determine cos2x if sin^4 x = 25/36, the solution is in the first quadrant.
Answer by reviewermath(1029) About Me  (Show Source):
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Q: Determine cos2x if sin^4 x = 25/36, the solution is in the first quadrant.
Tutorial:
sin^4 x = 25/36
Get the square root of both sides
sin^2 x = 5/6
[We disregard the negative root since the solution is in the first quadrant]
Use the double angle identity cos2x = 1 - 2sin^2 x
cos2x = 1 - 2(5/6) = highlight%28-2%2F3%29