Michigan Algebra I Sept. 2012

For odd polynomials that have several terms, they will only have an inverse if the sum of these terms is always increasing or always decreasing. Adding together terms that have odd powers with positive coefficients will create a graph that is continuously increasing and will therefore have an inverse that is a function. Another way to determine if the function has an inverse is by graphing the original function and then checking to see if the graph passes the horizontal line test. The horizontal line test asks the question, "Will a horizontal line pass through the graph and touch the graph in only one point?" If the graph passes the horizontal line test, the inverse will be a function.