Texas Instruments TITANIUM TI-89 - Manual (Page 90)

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2. Display the Home screen. Then store the
radius, 5, in variable r.
Press " 5 9 j R ¸
3. Display and clear the Y= Editor . Then
define y1(x) = , the top half of
a circle.
In function graphing, you must define
separate functions for the top and bottom
halves of a circle.
Press 8 # , 8 ¸ ¸ 2 ]
j R
Z 2 | X Z 2 d ¸
4. Define y2(x) = , the function for
the bottom half of the circle.
The bottom half is the negative of the top
half, so you can define y2(x) = Ly1(x).
Use the full function name y1(x) , not
simply y1.
Press ¸ ? Y 1 c X d ¸
Steps and keystrokes Display
5
!
r
r 2 x 2 – ( )
r 2 x 2 – –