Double-Angle and Half-Angle Formulas Forums Main Page › Forums Main Page › Precalculus › Trigonometric Equations and Identities › Double-Angle and Half-Angle Formulas This forum has 1 topic, and was last updated 11 years ago by Sharma. Viewing topic 1 (of 1 total) Topic Voices Posts Last Post Deriving Trig Formulas (lesson) Started by: Sharma 1 1 11 years ago Sharma Viewing topic 1 (of 1 total) You must be logged in to create new topics. Log In Username: Password: Keep me signed in Log In