Lesson plan

Find the value for angles at sine, cosine, and tangent on the x and y axis by using the unit circle and reference angles


You have saved this lesson plan!

Here's where you can access your saved items.

Content placeholder

or to view additional materials


Big Ideas: The unit circle has a radius of 1, so sin (t) =y/1=y and cos(t) =x/1=x and any point on the unit circle (x, y) can be labeled (cos(t),sin(t)). Therefore cos(t) and sin(t) can be evaluated using the reference triangles derived from Pythagorean Theorem. A trigonometric ratio is a function that has a domain and can be graphed using the terminal ray of the unit circle. The sine and cosine functions have a period of 2pi and an amplitude of 1. The tangent graph is undefined at positive or negative pi/2 and has a period of pi . In this lesson, students will be introduced to domain of the trig functions by looking at what happens on the x and y axes. Students will use their previous knowledge of the unit circle, reference triangles, and reference angles to understand what happens on the axes. This lesson will support the next lesson by allowing students to have exposure to trig functions being undefined in certain places because we cannot divide by zero. Vocabulary: Quadrantal Angles Special Materials: Graph Paper