Proving Identities with Hyperbolic Functions

Because of the e-based definitions of our hyperbolic functions sinh, cosh, and tanh, doing proofs with them can be quite rewarding. Here, we preview some of the identities for hyperbolic functions, which are in many ways analogous to the identities of trigonometric functions. We wrap up the video with two proofs. We first prove that cosh is an even function, and then we prove the sum-of-angles formula for cosh.