Index:
(There are forty more FAQs on page 1. Click page
2 under TI FAQs
in the navigation panel to
go there.)
(41) How do I make the screen brighter on a TI-83Plus?
(42) How can I find the area under a curve on a TI-83 Plus?
(43) Our professor wants us to show our work on a Simplex problem.
Can I use a TI-83Plus to do the row operations by hand?
(44) How do I do a scatter plot on a TI-83 Plus?
(45) How do I do an x-y line chart on a TI-83 Plus?
(46) How do I do a histogram on a TI-83 Plus?
(47) When I do fPart of a number like (4/3)3, I get 1. Why is that?
(48) Is there a way to keep from accidentally changing or deleting
programs?
(49) During the summer when I'm not in school, should I remove the AAA
batteries?
(50) Why will I loose my programs if I remove all batteries.
(51) What's the purpose of garbage collect.
(52) Should I run garbage collect periodically?
(53) You say that the TI-83 Plus and the TI-84 Plus use the same CPU.
I know enough about electronics to say that if they have
the same CPU, they run at
the same speed.
(54) Will your program FACTOR solve equations like 4sec^{2}x +
cotx -7?
(55) What is the main difference between the TI-83 Plus and the TI-84 and
how do the prices compare?
(56) I get an error message doing IRR. Why?
(57) How do I write a program for my TI-84 on my computer?
(58) How do I transfer a program from my computer to my TI-84 calculator?
(59) How do I transfer a program from my calculator to my computer?
(60) My quartile values don't agree with Minitab. Is there something
wrong with my calculator?
Revised: 2/11/10
Answers:
(41) How do I make the screen brighter on a TI-83Plus?
Press 2nd; then press the up arrow. If the screen is not set to
maximum, it should get brighter. If you get it too bright the down arrow
will decrease the brightness.
_______________
(42) How can I find the area under a curve on a TI-83Plus?
1) Press Y=, and enter your function in the usual manner in the Y1=
position.
2) Press 2nd; then CALC (2nd function of TRACE).
3) The calculator will go to the graphing screen and ask for the lower
limit. There are two ways to enter the limit: a) Just punch in
the number and press ENTER, and b) Move the cursor to where you want it
and press ENTER.
4) The calculator will now ask for the upper limit. Enter that in
either of the above ways. The area will be displayed after you enter the upper
limit.
__________________
(43) Our professor wants us to show our work on a Simplex problem.
Can I use a TI-83Plus to do the row operations by hand?
Well, yes, all of the gory details of row operations are in FAQ 21 on the
first page. So, I'll just give you a summary here.
First of all, I suggest that you enter your first tableau in matrix [B], and
then use STO to transfer it to matrix [A]. That way you can work on matrix [A],
and if you make a mistake you won't need to re-enter the original matrix.
Just transfer it from [B] to [A] again. (If you don't know how to enter
the first tableau see FAQ 19 on the first page.) So, you'll need several
row operations described as follows:
1) Multiply one row by a number and add it to another
number. Say, multiply row 2 by -2 and add that to row 2.
a) From the home screen, press 2nd, MATRIX; scroll over to MATH; scroll
down to item F, and press ENTER. You should now have *row+( on your home
screen.
b) Now you want to enter the multiplier, letter of the matrix, row number
multiplied by, row number to replace in that order. Do this: Enter
-2, press the comma button, press 2nd, MATRIX, ENTER. You should now have
*row+(-2, [A] on your screen. DO NOT enter [A] with the brackets and the
letter A.
c) Now press the comma button, enter 1; press the comma button and
enter 2. You should now have *row+(-2,[A],1,2 on your screen.
d) Press STO, 2nd, MATRIX, ENTER.
e) You should now have *row+(-2,[A], 1,2►[A]
on your screen. DO NOT enter [A] with the brackets and the letter
A. (Note carefully that if you don't add the STO, [A], then matrix A will
not be changed in your calculator. Also notice that you can either
close the parentheses after the last row number or leave them open.)
Note that if you have another
operation of this type you can press 2nd, ENTER,
and then edit the entry that appears for the proper multiplier and row numbers.
2) Multiply a row by a number.
Now, multiply row 2 by -1/5 as follows:
*row(-1/5,[A],2►[A].
3) Add two rows say 1 and 2.
If you want to add two rows; then the syntax is this: row+(matrix
letter, row to be added, row to be replaced)►[A]
4) Swap two rows.
To swap rows, use this syntax: rowSwap(matrix letter, first row,
second row►[A].
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(44) How do I do a scatter plot on a TI-83 Plus?
First you need to get your data into lists.
1) First go to the graphing screen by pressing the Y= button and
deselecting any functions so that they won't be entered on your graph.
2) Press
[STAT], [ENTER]
3)
Then enter the data-point numbers ( the x-values) in L1 and the
corresponding values (y-values) in L2. (If your data is not in order
you can sort in order by pressing [STAT], select 2, SortA( or SortD( for
descending order. SortA( , or SortD( will be posted
to the home screen. Press [2nd], L_{1}, 2nd, L2, [ENTER]. Be
careful! If your data in L_{2 }is not in ascending order when
correlated to L_{1, }then your data in L_{1} and L_{2}
will not be correlated correctly.)
4)
Press
[2nd], [QUIT]
5) Press [2nd], [STAT PLOT] and press [ENTER] to turn Plot 1 on.
6) Cursor to the scatter diagram on Type and press [ENTER] to highlight the
scatter diagram.
7) Enter L_{1} in the Xlist, and L_{2} in the Ylist (do
this by pressing 2nd and the appropriate list button); then select
the type marker you prefer. (I like the + symbol. ).
8) Press [GRAPH] and the scatter plot will
appear on the screen.
______________________
(45) How do I do an x-y line chart on a TI-83 Plus?
Do that the same
as the scatter plot in FAQ 44 above except that when you select the type, choose
the line symbol rather that the scatter symbol.
_____________________________
(46) How do I do a histogram on a TI-83 Plus?
This procedure will do a simple histogram in which the calculator selects the class width.
First you need to get your data into lists.
1) First go to the graphing screen by pressing the Y= button and
deselecting any functions so that they won't be entered on your graph.
2) Press
[STAT], [ENTER]
3) Then enter the data-point numbers ( the x-values) in L_{1}.
4)
Press
[2nd], [QUIT]
5) Press [2nd], [STAT PLOT] and press [ENTER] to turn Plot 1 on.
6) On the next screen highlight ON to turn the plot on, highlight the
histogram symbol and enter the list number for the data in Xlist, (for example L_{1}).
Leave Freq at the default of 1 unless you have "tabled" data, in which case you
will not use this method.
7) Press ZOOM; then 0 (ZoomFit) and your histogram will be displayed.
8)
You can use [TRACE] to display the value and boundaries of a particular bar on
the histogram.
If you want to set your own classes, go to FAQ 32 on page 1. You can get there
by going to the navigation bar to your left and clicking on More Detailed Page
1.
_________________________
(47) How do I do a regression and graph the scatter plot and the
regression equation on the same axis on a TI-83 Plus?
First you need to get your data into lists.
Press [STAT], [ENTER]
Then enter the data-point numbers (the x-values) in L1 and the corresponding
values (y-values) in L2.
Press [2nd], [QUIT]
Now, to do the scatter plot.
Now, you want to put the scatter plot on the screen with the graph. So do this:
1) Press [2nd], [STAT PLOT] and press [ENTER] to turn Plot 1 on.
2) Cursor to the scatter diagram on Type (the first icon) and press [ENTER] to
highlight the scatter diagram.
3) Enter L1 in the Xlist, and L2 in the Ylist; the select the type marker you
prefer. (I like a + ).
4) Press [GRAPH] the scatter plot will appear on the screen.
_______________________
(47) When I do fPart of a number like (4/3)3, I get 1. Why is that?
Bottom line: I don't know. But...I do have a guess that goes
something like this: When the calculator calculates 1/3 it comes up with
.3333333333. Now, if we multiply that 3, by hand, we'll get .9999999999.
But if you do it on the calc, you'll get 1. So, my guess is that the fPart
decides that .9999999999 is a fractional part, but the display prints it as 1.
If you have some free time, you could check this out and see if it holds water.
The practical implications of this quirk are that if
you're multiplying a proper fraction by a whole number, e.g., (6/5)5, the fPart
gives zero as expected. But when you do an improper fraction such as the
one you gave, you may get 1, 0, or a number like 1E-12 depending on your
improper fraction.
______________________________
(48) Is there a way to keep from accidentally changing or deleting
programs?
Yes, you can archive the program; then un-archive it when you want to make
deliberate changes. Here's how to archive a program.
a) Press 2nd, MEM, 2. (Pressing 2 selects 2:Mem
Mgmt/Del...)
b) Press 7 (for Prgm), ENTER.
c) Select the program you want to archive and press ENTER. An
asterisk will appear opposite the
program name indicating that it is
archived. With that, the program will be protected from being
deleted even when you upgrade the operating
system.
When you want to un-archive the program and make some changes, do the following:
a) Press 2nd, MEM, 2. (Pressing 2 selects 2:Mem
Mgmt/Del...)
b) Press 6 (to select Unarchive).
c) Press PRGM, select the archived program you want to un-archive
and press ENTER
d) Press ENTER again and the program will be un-archived and
available for editing.
______________________________________
(49) During the summer when I'm not in school, should I remove the AAA
batteries?
No, leave them in. When you remove the AAA batteries, the power
for the RAM is supplied by the small circular battery (CR1616 or CR1620.)
If you leave the AAA batteries out too long, the circular battery will be
discharged and you will lose any programs that you have in RAM..
_____________________________________
(50) Why will I loose my programs if I remove all batteries.
Well, I'm not exactly sure why you'd want to remove all of the batteries,
but if you do, you'll lose anything that is stored in RAM. Programs and
applications that have been stored in flash ROM, archived programs, will not be
lost. But any un-archived programs will be lost since they are
stored in volatile memory. It's just like when you turn off your computer,
you lose anything that hasn't been stored on a hard drive.
___________________________________
(51) What's the purpose of garbage collect.
Well, without going into a lot of hand waving, you can think of it as
being something like defrag on your computer. Only applications can cross
sector boundaries in your flash ROM. So, if you have a lot of archived
programs and variables, you'll eventually end up with a fragmented flash ROM.
_______________________________
(52) Should I run garbage collect periodically?
For myself, I just let it go because it can take some considerable time
to execute the garbage collect procedure. I have a lot of programs that
I've spend a lot of time on, so to be ultra-safe, I back up my calculator
before I'll let the calculator run garbage collect. That can take quite a
lot more time. Anyway, when you try to archive a program
with insufficient memory the calculator will ask you if you want to
garbage collect. Of course, if you're a gamer or some other sort of guru
and worry about all the nitty-gritty you can always run it.
__________________________________
(53) You say that the TI-83 Plus and the TI-84 Plus use the same CPU.
I know enough about electronics to say that if they have the same CPU, they run
at the same speed.
This is not really a calculator question, so I'm
reluctant to deal with it, but here goes anyway. I'm not sure if
you're misinterpreting what I said or if you're confusing execution efficiency
with speed. I'm pretty sure what I said was that both use the Z-80 CPU.
Now, I'm not an expert on CPU architecture, but I'm pretty sure that if one Z-80
takes, say, three clock cycles to do a particular operation, then another Z-80
will take the same number of clock cycles. But if, for example, the
time for a clock cycle is cut to 1/3 its former time, the speed for that
operation will be roughly three times as fast.
Clock speed is highly dependent on technology and chip layout
efficiency. So, let's say that if the Z-80 of the TI-83 Plus is 3-micron
technology (admittedly pretty old stuff); then if implemented in
.35- or .25-micron technology, for example, the clock speed could be much
faster. The smaller linewidths would result is shorter interconnect lines,
and, therefore, lower RC products; the transistors will be faster
because of the shorter channel lengths; possibly some timing issues will be
resolved due to a smaller chip, and, depending on the metallization thickness,
possible even a smaller RC product per unit length of interconnect.
That's enough. Back to calculator questions.
----------------------------------------------------------------
(54) Will your program FACTOR solve equations like 4csc^{2}x +
cot x -7?
No, you must first do some substitution.
csc^{2} x= 1+cot^{2} x. After
substitution you have:
4(1+cot^{2} x) + cot x - 7
4cot^{2} x
+ cot x -3
This is fairly easy to factor by trial and error, but, if you
want, you can let x = cot x with the resulting equation of
4x^{2} +x -3. You can plug that into my
program, and it will give you the factors in terms of x. You will
need to
replace each "x" in the factors with cot x to get your
factorization.
__________________________
(55) What is the main difference between the TI-83 Plus and the TI-84
and how do the prices compare?
The major differences between the TI-84 and the TI-83 Plus are that the
TI-84 has more memory, operates at a faster clock speed (about 2.5 times), and
has more applications loaded. Frankly, you might not notice the speed unless
you're a gamer or running some long programs. Although the TI-84 has more
applications loaded, you can download some of these free for the TI-83 Plus.
The TI-84 also has a clock, and the TI-83 Plus doesn’t if that’s important to
you.
There are also some of new statistics functions is the TI-84 Plus Silver
Edition. These are as follows: Manual Fit under the STAT>Calc menu; X2 GOF-Test
(X 2 means Chi-squared); and InvT under DISTR. Frankly, I’m especially glad to
see the InvT because I had to write a program for the TI-83 Plus to do that, but
many students don’t have it. There are also several Catalog items that
may or may not have importance to you. Here’s a list that I got somewhere, but
I’ve never really check it out completely: χ²GOF-Test , checkTmr , ClockOff and
ClockOn , dayOfWk , ExecLib, getDate, getDtFmt, getDtStr, getTime, getTmFmt,
getTmStr, invT , isClockOn , LinRegTInt, Manual-Fit, OpenLib, setDate, setDtFmt,
setTime, setTmFmt , startTmr , timeCnv. Many of these are used in programs.
You should bear in mind that the TI-83 Plus possibly could not be produced much
longer.
If you're into games or you plan to use your calculator for many
years, and if you're not on a tight budget, you might want to go with the
TI-84. Some schools that I know of, including ours, are migrating to the TI-84
Plus regular or Silver Edition, but you wouldn’t notice the difference with a
TI-83 Plus, except, MAYBE, in a statistics class. You can always use my program
for InvT J. It’s on my website in
the statistics user guide.
As to price, they vary all over the place, depending on where
you live. Check your Sunday newspaper supplement. Be sure to include such
places as Office Depot, Office Max, Staples, and Wal-Mart.
__________________________
(56) I get an error message doing IRR. Why?
1) If the first and last cash flows
have opposite signs, you should get an IRR without problems.
2) If they do not have opposite signs, you may have problems
according to the following:
a) If the cash flows all have negative signs, there will be
no IRR.
b) If there are relatively small positive cash flows between
negative first and last cash flows, you may
either not obtain a solution or may get an invalid
value. Of course, there's a vertical asymptote at
-100%, but often you can run into problems considerably before you get there.In this situation,
if you insist on solving this type problem you can graph it if the number of cash
flows does not make
the task too arduous.
Very briefly, what you want to do is graph the following:
Y1=C(0)+C(1)/(1+x)+C(2)/(1+x)²+C(1)/(1+x)^{3}+...C(n)/(1+x)^{n}
As a first try, set Xmax =2 and Xmin=-2.You can then find the value of the interest, X, using
the
2ND, CALC, Zero, method discussed elsewhere in these documents.
Let's take an example of
-500, 100, 200 , A, just to make the math simple. As A becomes
increasingly negative, the two
solutions move closer together so that at -63 the solutions about are -62% and
-50.7%. But if
A=-65 both of those solutions greater than -100% disappear and the calculator
accurately gives
an error message. Bottom line: If you plug in a negative number chosen at
random, your calculator
is not malfunctioning if it gives an error message.
_____________________
(57) How do I write a program for my TI-84 on my computer.
Well, there may be more
than one way to do it, but here's the way I do it. First you must have the
Graph Link software for
the TI-83 Plus calculator.
That can be downloaded free from the TI Website. Once you get that installed, just click on the icon
and the application will
open. It's pretty straightforward from that
point. I suggest you save the file to a folder that you will
use to
transfer the program to your calculator. I will deal
with that transfer in the next FAQ.
________________________
(58) How do I copy a program from my computer to my TI-84 calculator?
Here's the way I do
it.
a. Open TI-Connect and
connect the calculator to the computer with the USB cable.
b. Click on the TI-Device
Explorer icon.
c. Open the folder
where the program you want to copy to the calculator is stored.
d. Drag that file to the
TI-Device Explorer folder.
e. Copying of the file
will begin in a half minute or so.
_______________________________
(59) How do I copy a program from my TI-84 calculator to my computer?
a. Open TI-Connect and
connect the calculator to the computer with the USB cable.
Make sure the
calculator is on.
b. Click on the TI-Device
Explorer icon.
c. After the connection to the
calculator is established and the list is displayed, expand Program by
clicking on the + mark
beside “Program.”
d. Highlight the program that you
want to copy to the computer.
e. Click on the File menu and select
Copy to PC.
f. The folder "My Documents" will
appear with the folders listed. Select the folder where you want to store the
program and
open it.
g. Copying the file will begin
shortly.
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(60) My quartile values don't agree with Minitab. Is there something wrong
with my calculator?
Probably not.
There is no standard method for calculating quartiles. The TI calculators
use a method by
Moore and McCabe.
Minitab, I believe, uses uses a basic Mendehnall and Sincich method but
with interpolation rather than
rounding.
.