Several factors can be responsible, including: 1  Heredity: If your dad had oily hair, chances are you will, too. 2  Hormonal fluctuations: In adult women, it may come with the menstrual cycle or using birth control pills. 3  Bulking up: Excessive oil is a side effect of using androgenic hormones to increase body mass.
At first glance, a function looks just like a relation. 1  It's a set of ordered pairs such as { (0,1) , (5, 22), (11,9) }. 2  Like a relation, a function has a domain and range made up of the x and y values of ordered pairs.
3.1 Functions A relation is a set of ordered pairs (x, y). Example: The set {(1,a), (1, b), (2,b), (3,c), (3, a), (4,a)} is a relation A function is a relation (so, it is the set of ordered pairs) that does not contain two pairs with the same first component.