Fmax(), Fmin(), Fnoff – Texas Instruments TITANIUM TI-89 User Manual
Page 821: Appendix a: functions and instructions 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)|x1
¸
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)
.