Texas Instruments TI-89 Manual Do Utilizador

Basic Function Graphing

332

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

Finding y(x) at a Specified Point

1. From the

Graph

screen, press

‡ and select

1:Value

2. Type the x value, which must be a real value between

xmin

and

xmax

. The value can

be an expression.

4. Press

D or C to move the cursor between functions at the entered x value. The

corresponding y value is displayed.

If you press

A or B, the free-moving cursor appears. You may not be able to move it

back to the entered x value.

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.

3. Press

¸.

The cursor moves to that x value on the
first function selected in the Y= Editor,
and its coordinates are displayed.

Math Tool

Description

y1(x)=1.25x

cos(x)