Trig Identities for Pre-Calculus - dummies

By Yang Kuang, Elleyne Kase

Part of Pre-Calculus For Dummies Cheat Sheet

Of course you use trigonometry, commonly called trig, in pre-calculus. And you use trig identities as constants throughout an equation to help you solve problems. The always-true, never-changing trig identities are grouped by subject in the following lists:

A list of trigonometry identities grouped by subject