My TI-84 plus displays -2^2=-4. That is incorrect. What is wrong?

You apparently have your calculator set to display no digits to the right of the decimal point. 5/2 is 2.5, which rounds to 3, and 50/100 is 0.5, which rounds to 1.

To change the display setting, press MODE, highlight the desired settings on the first two lines, then press ENTER followed by 2ND QUIT. Try setting "NORMAL" and "FLOAT" and see what results you get now.

Is it somehow preventing you from graphing, or are you simply not getting the graph you expect?

Most likely you have the angular mode set wrong. You probably want it set to radians. Press MODE, move to the third line, highlight RADIAN, press ENTER, then 2ND [QUIT].

If it's not the angular mode, please reply to this post and give an example or two.

The Mode settings determine how entries are interpreted and how
answers are displayed on the TI-84 Plus. At first set option full screen and then folow next:If you cannot see anything on the screen, you may need to adjust the graphing TI 84 calculator contrast :
1.To darken the screen, press and release 2nd key, and then press and hold up-arrow key until the display is sufficiently dark.
2. To lighten the screen, press and release 2nd key, and then press and hold down-arrow key until the display is sufficiently light.

Hi purzabumafu8,

You need to re-install the Ti 84 Plus OS on both calculators, ASAP!!! You can fix these problems by installing the newest Ti 84 Plus 2.55v. MP OS, operating system. Use fresh batteries.

If you have a friend that has a Ti 84 Plus or, Ti 84 Plus Silver Edition you can connect the two calculators together through the USB or, IO link ports. Then they can send you a copy of their OS, while you receive it on your Ti 84 Plus. Hopefully, your friend will have Ti84 Plus 2.55v. MP OS on their calculator or, it might not work. Link the two calculator together through the USB or, IO link ports with the proper cable. If don't have another reliable calculator to connect too, you'll have to connect the calculator to a computer to download the OS, goto Procedure 5. If your downloading off another calculator goto Procedure 1.

Important Note: Never disconnect a TI Connectivity Cable during a transfer. Lost of power during installation of OS will destroy your calculator.

Procedure1. Procedure to linking to another calculator.
On their calculator press, [2nd][Link][G] [Right-Arrow]. On your calculator press, [2nd] [Link] [Right-Arrow] [Enter] and, then press [ENTER] on their calculator too. Their calculator should say, "TRANSMIT" and, your's will say "Receiving." Then on both calculators once transfer is complete press, [2nd][MODE] to quit and, return to the Home screen. If the OS was transferred then your finished with these procedures. If your calculator won't turn on or, is locked up try the Procedure 2, below.

Procedure 2.

Remove one of the AAA batteries. Press and hold the [DEL] key. While holding [DEL], reinsert the AAA battery and then turn the calculator on. The calculator should display
"Waiting...Please install calculator software now". If calculator did not turn on or, is still locked up goto Procedure 3, unless already did Procedure 3, then goto Procedure 4. If you calculator does come on and is responding and, your connect to another calculator goto Procedure 1. If you calculator does come on and is responding and, your connect to a computer goto Procedure 7.

Procedure 3.

Remove all of the batteries including the round lithium battery for 5 minutes. After the 5 minute period, reinsert all of the batteries and turn the calculator on. Adjust the contrast if necessary. Goto Procedure 2.

Procedure 4.

If the above process did not work. Try re-doing the Procedure 2, and, this time extend the time in Procedure 3, by 5 minutes to 10 minutes before you put all the batteries back in the calculator. These calculators can be a little stubborn at times so, keep trying Procedure 2.

Procedure 5.

If you can't find a calculator to connect too, you can connect your Ti 84 Plus to a computer that has Ti Connect software on it. If you need to connect your Ti 84 Plus to a computer make sure the Ti Connect software is operating properly. You do not want any hang-ups while installing the Ti 84 Plus OS.
Procedure 6. Procedure to installing the latest Ti84 Plus 2.55v. MP OS. TI OSDownloader does not always install the latest OS.
You can get the latest copy of Ti84 Plus 2.55v. MP OS and, guidebook by going to the Texas Instruments web site. You can get to that site instantly by clicking, "Ti 84 Plus 2.55v. MP OS!" Once your at the Ti site click the Download Item, "Ti84 Plus family operating system". Next you can login or, click "continue as guest". I'd would click the "continue as guest". Once you have click, "continue as guest" the Ti84 Plus family operating system will download to you.
Next, click "SAVE" and then a window to a folder will pop up. It is probably a window to a folder that you download too. If so, you may want to change it and, save to this folder, "My Documents \ My TI Data \ Downloads". You can also go back and, download the Ti 84 Plus guidebook too, if needed. If your calculator will not turn on or, is locked up goto Procedure 2. Or else goto Procedure 7.

Procedure 7.
Important Note: Never disconnect a TI Connectivity Cable during a transfer. Lost of power during installation of OS will destroy your calculator.
Link your computer and, Ti 84 Plus calculator with the USB cable or, Direct Black Link cable that came with the Ti 84 Plus calculator. Next, drag the Ti 84 Plus 2.55v MP OS that you saved earlier in "My Documents \ My TI Data \ Downloads" out of that folder and, drop it in the "Ti Connect" icon on the desktop. Click, "Continue" when the "Erase Warning" pops up and, the new Ti 84 Plus 2.55v MP OS will begin to install. Next, the Ti Device window should pop up and, highlight the port when it finds what your Ti 84 Plus is using, USB1 cable or, Direct Black COM1.

When the Ti Device Explorer finds and, highlights your calculator's information click, "Select." Then click, "Yes" when the next window shows up with your calculator's information and, the OS will continue to download. Upon completion the newest Ti 84 Plus 2.55v. MP OS will be installed.
If you run into any trouble with software or, drivers just comment to what failed at this posting and, I'll be glad to help you.

Hello,
Contact [email protected] or www.ti.com/calc .
Hope it helps

Check the following:

TI-84 Plus TI-84 Plus Silver Edition Guidebook

TI-84 Plus TI-84 Plus Silver Edition Guidebook

Introduction tothe TI-83 Plus and TI-84 Plus



A collection of activities for the TI-83 and TI-84 Plus


Part II: Texas Instruments TI-83, TI-83 Plus, TI-84 Plus Graphics

The comma key on the TI 84 SE is above the 7 key, and it is just left of (, right of x squared, and below SIN. thats where the "," key is. If you're asking something else, please clearify. My understanding is that you don't know where the comma key is. 

nderiv(nderiv(sin(x),x,x),x,2)

This is kinda a weird situation. Because it's usually the other way around. Your ram will clear if your calculator is frozen. So take out all 5 batteries from the back. Even the back up battery. Then reset it again. 2nd then + then 7 then 1 Then 2. Good luck.

Hello,
If number format in MODE is set to Normal, and if the (absolute value of) the number is smaller than 0.001,the calculator displays it in scientific notation( with the E). By the way E( ) stands for x10^( ).