Texas Instruments TI-89 Titanium - Page 207

Appendix A: Functions and Instructions 201
limit() uses methods such as L’Hopital’s rule, so
there are unique limits that it cannot determine. If
expression1 contains undefined variables other
than
var , you might have to constrain them to
obtain a more concise result.
Limits can be very sensitive to rounding error.
When possible, avoid the
APPROX setting of the
Exact/Approx mode and approximate numbers
when computing limits. Otherwise, limits that
should be zero or have infinite magnitude
probably will not, and limits that should have
finite non-zero magnitude might not.
limit(a^x,x,ˆ) ¸ undef
limit(a^x,x,ˆ)|a>1
¸ ˆ
limit(a^x,x,ˆ)|a>0 and a<1
¸ 0
Line CATALOG
Line xStart , yStart , xEnd , yEnd [, drawMode ]
Displays the Graph screen and draws, erases, or
inverts a line segment between the window
coordinates (
xStart , yStart ) and ( xEnd , yEnd ),
including both endpoints.
If
drawMode = 1, draws the line (default).
If
drawMode = 0, turns off the line.
If
drawMode = ë 1, turns a line that is on to off or
off to on (inverts pixels along the line).
Note: Regraphing erases all drawn items. See
also
PxlLine.
In the
ZoomStd window, draw a line and then
erase it.
Line 0,0,6,9 ¸
@ "
H ¥ "
Line 0,0,6,9,0
¸
LineHorz CATALOG
LineHorz y [, drawMode ]
Displays the Graph screen and draws, erases, or
inverts a horizontal line at window position
y .
If
drawMode = 1, draws the line (default).
If
drawMode = 0, turns off the line.
If
drawMode = ë 1, turns a line that is on to off or
off to on (inverts pixels along the line).
Note: Regraphing erases all drawn items. See
also
PxlHorz.
In a
ZoomStd window:
LineHorz 2.5 ¸
LineTan CATALOG
LineTan expression1 , expression2
Displays the Graph screen and draws a line
tangent to
expression1 at the point specified.
expression1 is an expression or the name of a
function, where
x is assumed to be the
independent variable, and
expression2 is the x
value of the point that is tangent.
Note: In the example shown,
expression1 is
graphed separately.
LineTan does not graph
expression1.
In function graphing mode and a ZoomTrig
window:
Graph cos(x)
@ "
H ¥ "
LineTan cos(x),p/4
¸