As you've seen, the trigonometric functions such as sine, cosine, and tangent are nothing more than ratios of particular sides in right-angle triangles. Note 8 These ratios depend only on the measure of an angle and have special names:
In the triangle above, the sine of angle A is defined as BC/AB. It is abbreviated sin A.
The cosine of angle A is defined as AC/AB. It is abbreviated cos A.
The tangent of angle A is defined as BC/AC. It is abbreviated as tan A. Note 9
Use the Interactive Activity to answer Problem C3 and C4 and to experiment with the trigonometric functions. For example, how big can sine get? What about cosine? How do you make them as big as possible? What about tangent? Does it seem to have a maximum value?
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