Trigonometric Ratios and the Unit Circle

The video tutorial explores trigonometric ratios, focusing on sine, cosine, and tangent. It explains their definitions in right-angled triangles and the limitations for angles beyond 90 degrees. The unit circle is introduced as a tool to extend these definitions. The tutorial covers how trigonometric functions behave in different quadrants and introduces the CAST rule to determine the sign of these functions. Finally, it demonstrates how to apply the CAST rule to solve problems involving angles greater than 90 degrees.

How does the tangent function behave in different quadrants of the unit circle?

How can you express sine 160 degrees in terms of acute angles?

What is the relationship between cosine 160 degrees and cosine 20 degrees?

Summarize the key points about the definitions and applications of trigonometric ratios.