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.
A function is a set of mathematical operations performed on one or more inputs (variables) that results in an output. For now, functions will take one or more real numbers as an input, and return a numerical output. In more advanced classes you'll learn about far more complex functions!