Sine and cosine are two key functions in trigonometry that relate angles to the ratios of sides in a right triangle. In the context of the unit circle, the cosine of an angle gives the horizontal coordinate, while the sine gives the vertical coordinate of a point on the circle. These functions are periodic, meaning they repeat in a regular pattern every full rotation, or 360 degrees. Sine starts at zero and goes up and down in a wave-like motion, while cosine starts at one and follows a similar

TRIGONOMETRY IDENTITIES: Trigonometric identities are mathematical equations that are true for all values of the variables involved, where both sides of the equation are defined. They are essential tools for simplifying trigonometric expressions and solving equations. These identities are derived from the definitions of trigonometric functions and the Pythagorean theorem. MAJOR TRIGONOMETRY IDENTITIES Reciprocal Identities: These relate each trigonometric function to its reciprocal: csc θ = 1/si