As you will learn in this topic, trigonometric functions can be expressed or described by the same means as the algebraic functions you have studied throughout this course: a rule (or the equation of the function); a table of values; a graph; and a written narrative (a word problem).

Given the rule of a function, you can create a table of values and then graph the function. Or you can input the rule in your graphing calculator to produce the graph. On the other hand, if you have a table of values, you can plot the points, analyze the pattern, and then complete the graph and determine the rule. Word problems demand all of your skills, as you must translate the written information into a mathematical expression or rule, from which you will determine the values and the graph.

	Before we begin this new study of trigonometric graphs, refresh your skills in using a function’s table of values or graph the function to identify the rule of the function. Click here to open the self-check.
	Practice determining the trigonometric ratios for the common angle measures in the special right triangles in preparation for this lesson. Click here to open the self-check.