Trigonometry

In a right triangle, sine (sin) is the ratio of opposite/hypotenuse, and cosine (cos) is adjacent/hypotenuse. On the unit circle, for angle θ, the point coordinates are (cos θ, sin θ).

Tangent (tan) is the ratio of sine to cosine, or in a right triangle, the ratio of opposite to adjacent side.

The unit circle is a circle with radius 1 centered at the origin. It's a fundamental tool for defining and visualizing trigonometric functions.

A radian is the angle where the arc length equals the radius. 360° = 2π radians.

Trigonometric identities are equations involving trigonometric functions that hold true for all angles.

Inverse trigonometric functions are the inverse functions of trigonometric functions, finding angles from ratio values. They include arcsin, arccos, and arctan.

The Law of Sines states that the ratio of each side length to the sine of its opposite angle is constant in a triangle.

The Law of Cosines relates one side of a triangle to the other two sides and their included angle. It generalizes the Pythagorean theorem.

Functions related to hyperbolas, similar in form to trigonometric functions but defined using exponentials.

Inverse functions of hyperbolic functions, expressible in terms of logarithms.