In mathematics, the trigonometric functions (also called the circular functions) are functions of an angle. They relate the angles of a triangle to the lengths of its sides. Trigonometric functions are important in the study of triangles and modeling periodic phenomena, among many other applications.
Yellow stool is typically due to an excess of fatty foods and grease in the diet. Mayo Clinic states that it can also be caused by a malabsorption disorder such as celiac disease.
Bright red stools are most commonly associated with problems near the end of the gastrointestinal tract (e.g., the rectum) and black stools typically suggest problems earlier in the gastrointestinal tract (e.g., the stomach or the beginning of the small intestine).