I. Reciprocal Identities
II. Quotient Identities
III. Pythagorean Identities
IV. Cofunction Identities
V. Even/Odd Identities
VI. Sum and Difference Identities
VII. Double Angle Identities
VIII. Half Angle Identities
IX. Product-to-Sum Identities
X. Sum-to-Product Identities
XI. Other Trig Formulas
Law of Sines
Law of Cosines
Area of Triangle
