Trigonometry › Pythagorean identities

CCSS.MATH.CONTENT.HSF.TF.C.8
Prove the Pythagorean identity sin²(θ) + cos²(θ) = 1 and use it to find sin(θ), cos(θ), or tan(θ) given sin(θ), cos(θ), or tan(θ) and the quadrant of the angle.

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