1. 5.4 The Graphs of Sine and Cosine Writing an equation from the graph
2. To write an equation: Determine whether to use sine or cosine If the y-intercept is in the middle of the graph, use sine If the y-intercept is at a maximum or a minimum, use cosine. Determine the amplitude of the function Determine the period of the function Use the period to find ω Determine the vertical shift Determine whether there is a reflection
3. Basic Equations *Note: A horizontal shift is also possible, but you will not use it today.