1
Download TI-92 - Cengage Learning
Transcript
26 Graphing Technology Guide: TI-92 5.5.4 Exponential Growth Model: The table shows the world population (in millions) from 1980 to 1992. Year 1980 1985 1986 1987 1988 1989 1990 1991 1992 Population (millions) 4453 4850 4936 5024 5112 5202 5294 5384 5478 Clear the previous data by going to the current variable in the Data/Matrix Editor and pressing F1 [Tools] 8[Clear Editor] ENTER. Follow the procedure described above to enter the data in order to find an exponential model that approximates the given data. Use 0 for 1980, 5 for 1985, and so on. The TI-92 will not compute the exponential growth model y = aecx. The exponential regression that the TI-92 will compute is of the form y = abx. To get this exponential growth model press F5[Calc] and set the Calculation Type to 4[ExpReg], the x variable to c1, and the y variable to c2. Then press ENTER to find the values of a and b (Figure 5.73). In this case, the exponential growth model is y = 4451(1.017454x). To convert this to the form y = aecx, the required equation is c = ln b, and the exponential growth model in this case is y = 4451ex ln 1.017454 or y = 4451e0.017303t. Figure 5.73: Exponential growth model If you wish to plot and graph the data, follow the method for linear regression. Set an appropriate range for the data and then press GRAPH. The data will now be plotted in the range. To graph the regression equation also, store the regression equation to a y plot that is free. As in the linear regression model, press Y= and inactivate or clear any other existing functions, then press GRAPH to graph the exponential growth model. Note that the exponential regression model does not need to be converted to the form y = aecx before graphing. Remember to clear or deselect the plot before viewing graphs of other functions. 5.6 Matrices 5.6.1 Making a Matrix: The TI-92 can work with as many different matrices as the memory will hold. Here’s how 3 5 1 −4 to create this 3×4 matrix −1 3 −1 −3 in your calculator. 2 0 −4 6 From the Home screen, press APPS 6[Data/Matrix Editor] 3[New]. Set the Type to Matrix, the Variable to a (this is the ‘name’ of the matrix), the Row Dimension to 3 and the Col Dimension to 4 (Figure 5.74). Press ENTER to accept these values. Copyright © Houghton Mifflin Company. All rights reserved.
