Using Math Tools To Analyze Functions - Texas Instruments TI-89 Manual Book

Using Math Tools to Analyze Functions

Overview of the
Math Menu
Note: For Math results,
cursor coordinates are
stored in system variables
xc and yc (rc and qc if you
use polar coordinates).
Derivatives, integrals,
distances, etc., are stored in
the system variable
sysMath.
122 Chapter 6: Basic Function Graphing
On the Graph screen, the ‡ Math toolbar menu has several
tools that help you analyze graphed functions.
Press ‡ from the Graph screen.
Math Tool Description
Evaluates a selected
Value
value.
Finds a zero (x-intercept), minimum, or maximum
Zero,
point within an interval.
Minimum,
Maximum
Finds the intersection of two functions.
Intersection
Derivatives Finds the derivative (slope) at a point.
‰
Finds the approximate numerical integral over an
f(x)dx
interval.
Finds the inflection point of a curve, where its
Inflection
second derivative changes sign (where the curve
changes concavity).
Draws and measures a line between two points on
Distance
the same function or on two different functions.
Draws a tangent line at a point and displays its
Tangent
equation.
Finds the arc length between two points along a
Arc
curve.
Depends on the number of functions graphed.
Shade
¦
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.
On the Derivatives submenu,
only dy/dx is available for
function graphing. The other
derivatives are available for
other graphing modes
(parametric, polar, etc.).
function at a specified
y(x) x