Part A: To get started, plot the 12 values on a graph. The number corresponding to the month is t or the independent variable and the average temperature for that month is vlt) or the dependent variable. The points should create a periodic pattern. Assume that the data is, in fact, periodic and use the graph to determine the following values for a sine and then a cosine function: y = a similar + c) + dandy = a cos(bt + c) + d . You do not have to hand in this graph, but it will help you complete the portfolio