Page 1: Trigonometric Functions of Acute Angles - Review
This page provides a comprehensive review of trigonometric functions of acute angles in right triangles, building upon knowledge from previous classes. It covers the definitions and key properties of sine, cosine, tangent, and cotangent.
The sine, cosine, tangent, and cotangent of an acute angle in a right triangle are defined as ratios of side lengths:
Definition: Sine of an acute angle is the ratio of the length of the opposite side to the length of the hypotenuse.
Definition: Cosine of an acute angle is the ratio of the length of the adjacent side to the length of the hypotenuse.
Definition: Tangent of an acute angle is the ratio of the length of the opposite side to the length of the adjacent side.
Definition: Cotangent of an acute angle is the ratio of the length of the adjacent side to the length of the opposite side.
The page also presents key trigonometric identities and relationships:
Highlight: For any acute angle x: sin²x + cos²x = 1
Highlight: tgx = sinx / cosx and ctgx = cosx / sinx
Highlight: tgx · ctgx = 1
Additionally, the document provides information on the ranges of trigonometric functions for acute angles:
Vocabulary: Sine and cosine of acute angles are values in the range (0, 1), while tangent and cotangent of acute angles are values in the range (0, +∞).
The page concludes with complementary angle relationships and special angle values (30°, 45°, 60°) for trigonometric functions.