When that is the case, we say that y is a function of x. Thus a "function" must be single-valued one and only one. For example, y 2 x 3. To each value of x there is a unique value of y.
Domain and range, the values that x may assume are called the domain of the function. We say that those are the values for which the function is defined. In the function y 2 x 3, the domain may include all real numbers.
X could be any real number. Or, as in Example 1 below, the domain may be arbitrarily restricted. There is one case however in which the domain must be restricted: A denominator may not be 0. When your books and teachers don't make sense, we do. Contact Us, legal, about, sitemap, mobile Apps, advertise, facebook, twitter, sparkNotes is brought to you by B N. Visit B N to buy and rent textbooks, and check out our award-winning tablets and ereaders, including Samsung Galaxy Tab 4 nook and nook GlowLight. In this function, x may not take the value 2. For, division by 2015 SparkNotes LLC, All Rights Reserved.