CIR - The Unit Circle Lesson

The Unit Circle

Recall: Rationalizing the Denominator

When a radical is left in the denominator you must rationalize!

Example: equation image indicator $LaTeX: \frac{5}{\sqrt[]{2}}:\frac{5}{\sqrt[]{2}}\left(\frac{\sqrt[]{2}}{\sqrt[]{2}}\right)=\frac{5\sqrt[]{2}}{2}$ $\frac{5}{\sqrt[]{2}}:\frac{5}{\sqrt[]{2}}\left(\frac{\sqrt[]{2}}{\sqrt[]{2}}\right)=\frac{5\sqrt[]{2}}{2}$

A Unit Circle is a circle with the radius equal to 1 and the center at the origin.

unit circle with points at (-1,0), (0, 1), (1, 0), and (0, -1)

We use our special right triangles, and our Unit Circle to place important angles and coordinates on the Unit Circle.

**SPECIAL NOTE** In the video below, the angle in the 3rd quadrant is labeled incorrectly. It should be labeled 225 degrees NOT 215 degrees.

IMAGES CREATED BY GAVS