Trigonometry Help

The lessons below cover identities and the more advanced formulas that come up once you have the basics of sine, cosine, and tangent down. Each lesson includes worked examples and the derivations behind the formulas.

Lessons

• Trigonometric Identities — a full reference list including Pythagorean identities
• Addition Formulas — sin(A+B), cos(A+B), and related formulas
• Double and Half Angle Formulas
• Derivatives of Trig Functions — how sine, cosine, and tangent behave under differentiation

Other Resources

For an introduction to the basic trig functions and the unit circle, these external resources are good starting points:

• Basic Trigonometry — Khan Academy intro to sine, cosine, and tangent
• Measuring Angles in Radians — why radians exist and how to use them
• Trig Functions — a review of all six functions from Paul's Online Notes
• Magic Identity — a visual mnemonic for the identities