If sin(x) = 1/27 (in Quadrant I), find cos(2x).
Added by Juan P.
Step 1
Using the Pythagorean identity: sin^2(x) + cos^2(x) = 1 (1/27)^2 + cos^2(x) = 1 1/729 + cos^2(x) = 1 cos^2(x) = 1 - 1/729 cos^2(x) = 728/729 cos(x) = sqrt(728/729) cos(x) = sqrt(728)/sqrt(729) cos(x) = sqrt(728)/27 ** Show more…
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