WEBVTT

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Here is the problem: Find sin, cos and tan of 1.2 on the unit circle.

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Unit circle values for 68.75493542° (1.2 rad).

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Convert radians to degrees (multiply by 180/pi).

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Find the coterminal angle between 0° and 360°. Add or subtract full turns of 360° (2pi); trigonometric values repeat every full turn.

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Locate the terminal side: in Quadrant I. In Quadrant I sine and cosine are both positive (“All Students Take Calculus”).

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Reference angle (acute angle to the x-axis).

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Evaluate the coordinates (this angle is not a multiple of 15°, so values are decimal approximations).

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Tangent equals sine divided by cosine.

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Reciprocal functions.

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So the answer is (cos theta, sin theta) approximately (0.3623577545, 0.932039086); tan theta approximately 2.572151622.

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68.75493542° (1.2 rad) ends in Quadrant I with a reference angle of 68.75493542°. sin theta approximately 0.932039086, cos theta approximately 0.3623577545, tan theta approximately 2.572151622, csc theta approximately 1.072916378, sec theta approximately 2.759703601, cot theta approximately 0.3887795694.

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cos squaredtheta plus sin squaredtheta equals 1 (must equal 1).