Operation Manual

8-6
DRAW
Operations
8208DRAW.DOC TI-82, Chapter 8, English Bob Fedorisko Revised: 02/09/01 12:23 PM Printed:
02/09/01 3:30 PM Page 6 of 16
Drawing Tangent Lines
While a graph is displayed, you can draw the tangent line of a function at a
specified point using the cursor. If a graph is not displayed, the instruction is
copied to the Home screen.
Directly on a Graph
1. When a graph of selected functions is displayed, select
Tangent(
from
the
DRAW DRAW
menu (item
5
).
2. Use
†
and
}
to move the cursor to the function for which you want to
draw the tangent line.
3. Use
~
and
|
to move the cursor to the point on the function at which
you want to draw the tangent line.
4. Press
Í
.
From the Home Screen or a Program
Tangent(
(tangent line) (
DRAW DRAW
item
5
) draws a line tangent to an
expression
in terms of
X
(such as
Y
1
or
X
2
) at point
X
=
value
(which can be
an expression).
expression
is interpreted as being in
Func
MODE
.
Tangent(
expression
,
value
)
For example, if
Y
1
=.2X
3
–2X+6
is the only selected function,
Tangent(Y
1
,3)
plots
Y
1
and draws the tangent to the function at
X
=3: