Geometry

Ellipse and its equation

Ellipse is twisted circle, it got major features and equation from circle.

Ellipse got TWO radiuses (or radii):

• Major radius: the longer one.
• Minor radius: the shorter one.

Reference Angle

The notion reference angle would be the very FIRST thing to understand before solving any trig equations.

First thing first, it’s always the angel with X-axis and Terminal Ray.

Unit circle

It’s a fairly fundamental tool for solving trigonometric problems.

Bisect

You can bisect a line segment, an angle, a shape, etc.

Bisector is the point or line or anything you use to divide things.
An angle bisector is a line, or you could say you draw a line bisects the angle.

Conic Sections

It’s something related to the previous topic Cross sections. It is a section (or a slice) through a Cone.

Equations of Circle

Definition of circle: The set of all points on a plane that are a fixed distance from a center.

Circle

“The circle is arguably the most fundamental shape in our universe.” — Sal Khan

Arc length