This posting describes how to use the TI-83Plus calculator to solve the Section Project, given recently in the Applied Calculus I class at Salve Regina University. To begin with, you should set up the TI-83Plus for statistical plotting. Press 2nd, Y= (STATPLOT): If Plot1 is set to off, select it and set it to on as show below. Next, press STAT, select EDIT, and enter the data: To determine a general exponential regression model, press STAT, then use the arrow keys to select CALC--> 0:ExpReg This should produce the following screen: Next, to see the graph of your exponential regression model together with a plot of the data perform the following steps; Press VAR and use the arrow keys to select Y-VARS -->1:FUNCTION-->1:Y1: This should produce the following screen. Press ENTER to determine the exponential regression model. To graph this model in the window [1 5] by [4 8], press WINDOW and set the values as shown: Next, press GRAPH to produce the following graph. If you want to see the correlation coefficient r and coefficient of determination r² (based on linearly transformed data (ln(y) = ln(a)+x ln(b)), press 2nd, 0 (CATALOG), select DiagnosticON, and press ENTER twice: If you repeat the computation of the exponential model after you've enabled DiagnosticON, you'll get the correlation coefficient r and coefficient of determination r² as shown: Once you've found the regression model, you need compute it's derivative. Recall that if f(x) = ab^x, then f'(x) = aln(b)b^x.