This trigonometry video tutorial provides a basic introduction to the double angle identities of sine, cosine, and tangent. It explains how to derive the double angle formulas from the sum and difference identities of sin, cos, and tan and how to use the double angle formulas to find the exact value of trigonometric expressions using right triangle trigonometry and SOHCAHTOA. This video contains many examples and practice problems for you to learn this material. Bearing Problems and Navigation: https://www.youtube.com/watch?v=cSKAqfGXOPI Two Triangle Problems - More Examples: https://www.youtube.com/watch?v=QM1T6eL8t48 Verifying Trigonometric Identities: https://www.youtube.com/watch?v=Rf05H8ogHLg Sum and Difference Identities: https://www.youtube.com/watch?v=gEhxBFQCYic Verifying Trig Identities With Double Angles: https://www.youtube.com/watch?v=Wh7hM_FsN3Y __________________________ Power Reducing Formulas: https://www.youtube.com/watch?v=U6yjjaK8aCc Half Angle Formulas: https://www.youtube.com/watch?v=9YI69okba3c Verifying Trig Identities Using Half Angles: https://www.youtube.com/watch?v=qWJ4HwJ_5LY Inverse Trig Functions With Double Angles: https://www.youtube.com/watch?v=waDbbpib9cM Right Triangle Trig With Half Angle Identities: https://www.youtube.com/watch?v=vEU25NlpaXA Product To Sum + Sum to Product Formulas: https://www.youtube.com/watch?v=8Prc7VGt40w ______________________________ Solving Trig Equations - Finding All Solutions: https://www.youtube.com/watch?v=kEcbxiLeGTc Solving Trig Equations With Multiple Angles: https://www.youtube.com/watch?v=eZPEW2hVUd0 Solving Trig Equations With Double Angles: https://www.youtube.com/watch?v=-R7394Dn854 Trigonometry Final Exam Review: https://www.youtube.com/watch?v=OAsbx4TEnL0 Final Exams and Video Playlists: https://www.video-tutor.net/ Full-Length Videos and Worksheets: https://www.patreon.com/MathScienceTutor/collections