Education Technology

Precalculus: Unit Circle
by Texas Instruments - Bell Ringer Lesson

Published on August 17, 2010


Students discover the relationship between the trigonometric functions sine, cosine, and tangent and the side length ratios of a right triangle.

Key Steps

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    Students engage in an exploration of points and angles on the unit circle.

    Right triangle relationships are utilized to develop the relationship between angles and coordinates.

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    Students link their prior knowledge of special right triangles to identify coordinates for 30, 45, and 60 degree angles on the unit circle.

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    After establishing relationships in Quadrant I, students extend their knowledge through the application of symmetry to angles in Quadrants II, III, and IV.