Texas Instruments PLUS TI-89 - Manual (Page 139)

122 Chapter 6: Basic Function Graphing
06BASFUN.DOC TI-89/TI-92 Plus: Basic Function Graphing (English) Susan Gullord Revised: 02/23/01 4:09 PM Printed: 02/23/01 4:18 PM Page 122 of 22
Press ‡ from the Graph screen.
Math Tool Description
Value Evaluates a selected y(x) function at a specified x
value.
Zero,
Minimum,
Maximum Finds a zero (x-intercept), minimum, or maximum
point within an interval.
Intersection Finds the intersection of two functions.
Derivatives Finds the derivative (slope) at a point.
‰ f(x)dx Finds the approximate numerical integral over an
interval.
Inflection Finds the inflection point of a curve, where its
second derivative changes sign (where the curve
changes concavity).
Distance Draws and measures a line between two points on
the same function or on two different functions.
Tangent Draws a tangent line at a point and displays its
equation.
Arc Finds the arc length between two points along a
curve.
Shade Depends on the number of functions graphed.
¦ If only one function is graphed, this shades the
function’s area above or below the x axis.
¦ If two or more functions are graphed, this shades
the area between any two functions within an
interval.
Using Math Tools to Analyze Functions
On the Graph screen, the ‡ Math toolbar menu has several
tools that help you analyze graphed functions.
Overview of the
Math Menu
Note: For Math results,
cursor coordinates are
stored in system variables
xc and yc (rc and
q c if you
use polar coordinates).
Derivatives, integrals,
distances, etc., are stored in
the system variable
sysMath.
On the Derivatives submenu,
only dy/dx is available for
function graphing. The other
derivatives are available for
other graphing modes
(parametric, polar, etc.).