Trigonometry

In a right triangle ABC

In a right triangle ABC with right angle at B, for angle A: sin A = opposite/hypotenuse (BC/AC), cos A = adjacent/hypotenuse (AB/AC), tan A = opposite

Key trigonometric values

Key trigonometric values: sin 0° = 0, sin 30° = 1/2, sin 45° = 1/√2, sin 60° = √3/2, sin 90° = 1; cos 0° = 1, cos 30° = √3/2, cos 45° = 1/√2, cos 60°

For complementary angles (angles that sum

For complementary angles (angles that sum to 90°): sin(90° - A) = cos A, cos(90° - A) = sin A, tan(90° - A) = cot A, and their reciprocals follow simi

Fundamental identities

Fundamental identities: sin²A + cos²A = 1, sec²A - tan²A = 1, cosec²A - cot²A = 1. These relationships hold for all values of angle A