posted by rick
The Pythagorean Theorem gives the relationship between the sides of a right triangle. The following identities show the relationships between the trigonometric functions of a particular angle.
sin2 θ + cos2 θ = 1
tan2 θ + 1 = sec2 θ
1 + cot2 θ = csc2 θ
Why then are these referred to as the Pythagorean Identities?