The Pythagorean trigonometric identity, also called simply the Pythagorean identity, is an identity expressing the Pythagorean theorem in terms of trigonometric...

are several equivalent ways for defining trigonometric functions, and the proofs of the trigonometric identities between them depend on the chosen definition...

between sine and cosine is sometimes called the fundamental Pythagorean trigonometric identity. In similar triangles, the ratios of the sides are the same...

basic relationship between the sine and the cosine is the Pythagorean trigonometric identity: cos 2 ⁡ ( θ ) + sin 2 ⁡ ( θ ) = 1 {\displaystyle \cos ^{2}(\theta...

In trigonometry, trigonometric identities are equalities that involve trigonometric functions and are true for every value of the occurring variables for...

cotangent identity Lagrange's trigonometric identities Morrie's law Proofs of trigonometric identities Pythagorean trigonometric identity Tangent half-angle...

widely used in the study of dynamical systems. Angle measure Pythagorean trigonometric identity Riemannian circle Radian Unit disk Unit sphere Unit hyperbola...

before the nineteenth century Pythagorean theorem Pythagorean triple Pythagorean prime Pythagorean trigonometric identity Table of Pythagoras, another...

^{2}x&=1\end{aligned}}} the last of which is similar to the Pythagorean trigonometric identity. One also has sech 2 ⁡ x = 1 − tanh 2 ⁡ x csch 2 ⁡ x = coth...

sides, expanding the squared binomial, and then applying the Pythagorean trigonometric identity cos 2 ⁡ γ + sin 2 ⁡ γ = 1 , {\displaystyle \cos ^{2}\gamma...