Texas Instruments TITANIUM TI-89 - Manual (Page 821)

Appendix A: Functions and Instructions 821
fMax() MATH/Calculus menu
fMax( expression, var )
⇒ ⇒ ⇒ ⇒ Boolean expression
Returns a Boolean expression specifying
candidate values of
var that maximize expression
or locate its least upper bound.
fMax(1ì (xì a)^2ì (xì b)^2,x) ¸
x =
a+b
2
fMax(.5x^3ì xì 2,x) ¸ x = ˆ
Use the “|” operator to restrict the solution
interval and/or specify the sign of other undefined
variables.
For the APPROX setting of the Exact/Approx
mode, fMax() iteratively searches for one
approximate local maximum. This is often faster,
particularly if you use the “|” operator to
constrain the search to a relatively small interval
that contains exactly one local maximum.
Note: See also fMin() and max() .
fMax(.5x^3ì xì 2,x)|x1 ¸
x = ë .816 ...
fMax(aù x^2,x) ¸
x = ˆ or x = ë ˆ or x = 0 or a = 0
fMax(aù x^2,x)|a<0 ¸ x = 0
fMin()
MATH/Calculus menu
fMin( expression, var )
⇒ ⇒ ⇒ ⇒ Boolean expression
Returns a Boolean expression specifying
candidate values of
var that minimize expression or
locate its greatest lower bound.
Use the “|” operator to restrict the solution
interval and/or specify the sign of other undefined
variables.
For the APPROX setting of the Exact/Approx
mode, fMin() iteratively searches for one
approximate local minimum. This is often faster,
particularly if you use the “|” operator to
constrain the search to a relatively small interval
that contains exactly one local minimum.
Note: See also fMax() and min() .
fMin(1ì (xì a)^2ì (xì b)^2,x) ¸
x = ˆ or x = ë ˆ
fMin(.5x^3ì xì 2,x)|x‚1 ¸ x = 1
fMin(aù x^2,x) ¸
x = ˆ or x = ë ˆ or x = 0 or a = 0
fMin(aù x^2,x)|a>0 and x>1 ¸
x = 1.
fMin(aù x^2,x)|a>0 ¸ x = 0
FnOff
CATALOG
FnOff
Deselects all Y= functions for the current
graphing mode.
In split-screen, two-graph mode, FnOff only
applies to the active graph.
FnOff [1] [, 2] ... [,99]
Deselects the specified Y= functions for the
current graphing mode.
In function graphing mode:
FnOff 1,3 ¸
deselects
y1(x)
and
y3(x)
.
In parametric graphing mode:
FnOff 1,3 ¸
deselects
xt1(t)
,
yt1(t)
,
xt3(t)
, and
yt3(t)
.