Experiments continue as shadows created on the ground and wall are used to form right triangles. Students also use the semicircle formed by the movement of the stick to develop the unit circle and to investigate how the unit circle relates to trigonometric function values. All the investigations are designed to help students see and understand the relationships between angles and lengths that underlie trigonometric functions. Included are interactive graphs of sine and cosine waves that illustrate the effects of changing frequency and amplitude values and of adding trigonometric functions. Also explained and illustrated are graphs for polar equations.
Surveying is discussed as a real world application of trigonometry.
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