Definition 3.1.1.
The fundamental trigonometric identities are
- Reciprocal Identities (Definition 1.4.2)
- Quotient Identities (Definition 1.4.3)
- Pythagorean Identities (Definition 1.5.20)
-
Odd-Even Identities (Definition 1.5.22)The cosine and secant functions are evenThe sine, cosecant, tangent, and cotangent functions are odd
- Cofunction Identities (Definition 1.4.7)