sin α = leg opposite to α / hypotenuse, cos α = leg adjacent to α / hypotenuse, tan α = leg opposite to α / leg adjacent to α, cot α = leg adjacent to α / leg opposite to α. Examples: sin α = a/c, cos α = b/c, tan α = a/b, cot α = b/a, sin β = b / c, cos β = a / c, tan β = b / a, cot β = a / b. Values of the trigonometric functions for 0°, 30°, 45°, 60°, 90°. Calculate these values. Examples: sin30° = 1/2, cos45° = square root of 2 / 2, tan30° = square root of 3 / 3 \cot0° ← not exists.