Use identities to find the indicated value for each angle measure. sin ? = 20/29, cos ? > 0. Find cos(2?)
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This is one of the Pythagorean identities in trigonometry. Given that sin θ = 20/29 and cos θ > 0, we can substitute sin θ into the identity: (20/29)^2 + cos^2 θ = 1 400/841 + cos^2 θ = 1 cos^2 θ = 1 - 400/841 Show more…
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