Pythagorean Identities Circle Identities

Trig identities relating sine with cosine, tangent with secant, and cotangent with cosecant. Derived from the Pythagorean theorem.

Pythagorean Identities

sin^{2} θ + cos^{2} θ = 1

tan^{2} θ + 1 = sec^{2} θ

cot^{2} θ + 1 = csc^{2} θ