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.
1 Itâs often normal for stool to change color. 2  In some cases, yellow stool may be a result of liver disorders, diet changes, or stress.  If yellow stool persists for several days, or if it is accompanied by other symptoms, you should contact your doctor.