This section introduces students to the unit circle as it builds on work with similar triangles and trigonometric ratios. First, students consider a context with repeating outputs. Throughout the section, students use contexts involving circular motion as they make sense of periodic functions and the unit circle.

Next, students use the Pythagorean Theorem to connect legs of a right triangle...

This section focuses on transformations of trigonometric functions.
Students have seen the effects of translations and scale factors on graphs in an earlier unit when they studied general transformations of functions and in a previous course when they studied quadratic equations and their graphs.

First, students are introduced to the amplitude of a periodic function in context, building from prior...

In this final section, students have the opportunity to apply their thinking from throughout the unit. As this is a short section followed by an End-of-Unit Assessment, there are no section goals or checkpoint questions.

This section develops sine, cosine, and tangent as trigonometric functions. This builds on work from an earlier course in which students worked with sine, cosine, and tangent ratios using right triangles, and then the work in a previous section in which students used expressions involving sine and cosine to locate points on a circle.

First, students examine graphs of functions...