Trigonometry in the Coordinate Plane: Sine, Cosine, and Tangent

This lesson covers the basics of trigonometry, focusing on sine, cosine, and tangent in the coordinate plane. It begins with a review of right triangle geometry and the Pythagorean theorem, introducing the acronym SOHCAHTOA for remembering trigonometric ratios. The lesson explains angles in standard position and how to use reference triangles to find trigonometric ratios. It also discusses the rotation of terminal rays and how to calculate sine and cosine at 90 degrees. An example problem is provided to illustrate these concepts, along with tips to avoid common mistakes.

How do you calculate the sine and cosine of 90 degrees?

Describe the process of finding the hypotenuse r using the Pythagorean theorem.

What common mistakes do students make when working with sine and cosine, and how can they be avoided?