HP 48gII - Manual (Page 443)

Page 13-8
maxima) of the function, to plot the derivative, and to find the equation of the
tangent line.
Try the following example for the function y = tan(x).
• Press „ô, simultaneously in RPN mode, to access to the PLOT
SETUP window.
• Change TYPE to FUNCTION, if needed, by using [@CHOOS].
• Press ˜ and type in the equation ‘TAN(X)’.
• Make sure the independent variable is set to ‘X’.
• Press L @@@OK@@@ to return to normal calculator display.
• Press „ò, simultaneously, to access the PLOT window
• Change H-VIEW range to –2 to 2, and V-VIEW range to –5 to 5.
• Press @ERASE @DRAW to plot the function in polar coordinates.
The resulting plot looks as follows:
• Notice that there are vertical lines that represent asymptotes. These
are not part of the graph, but show points where TAN(X) goes to ± ∞
at certain values of X.
• Press @TRACE @(X,Y)@, and move the cursor to the point X: 1.08E0, Y:
1.86E0. Next, press L@)@FCN@ @SLOPE. The result is Slope:
4.45010547846.
• Press LL@TANL. This operation produces the equation of the
tangent line, and plots its graph in the same figure. The result is
shown in the figure below: