Why does my t- 84 give a data type error when I ask it to write 9/(2+3i) as a fraction

To enter your equation press 12 then a/b (the fraction key). 12 will now be at the top of your fraction and there will be an arrow blinking in the bottom block. then press 2. If the part in brackets is also meant to divide into 12 then simply press open bracket ( 6 - 7 + 4 close bracket ) right arrow to get out of the fraction and then x 2. If the part in brackets is not meant to be divided into 12 then press the right arrow key before typing in the open bracket ( 6 - 7 + 4 etc.

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I am afraid you cannot do that with the TI83/84 Plus SE. The newer OS allows you to get results expressed as fractions, but not radicals. Sorry.
Your question seems to imply that you can do algebra with this calculator but that is impossible, unless you stored numerical values in variables a and b. In that case that is not doing algebra.

The TI-84 works with real fractions. It will not convert complex numbers to fractions.

You can convert the real and imaginary components to fractions separately. For your example, 1/(1+i) is .5-.5i. Converting .5 and -.5 to fractions, you get 1/2 + (1/2)i.

The TI-84 does not have a Computer Algebra System and therefore cannot perform this operation.

It can however find the value of a derivative at a single point on a function. Put the function into your Y= menu and graph it. Press 2nd and Trace to go to the calc menu and choose the "dy/dx" option. Type the x-value at which you want to evaluate the derivative and press enter.

To clean the slate so to speak, just reset the RAM.

1. Press [2nd][+] to access the (MEM)ory management function
2. Press [7:Reset]
3. Press [1:All Ram]
4. Press [2:Reset]
5. Press [CLEAR] to erase the "RAM cleared" Message

Calc

I assume you know how to enter data in your calculator. The keystrokes in the following pertain to TI92/92Plus/ Voyage 200 PLT. The main differences with the TI89/Ti89 Titanium is that the function keys F6,F7,F8 are not accessed directly but by the key sequences [2nd][F1], [2nd][F2], and [2nd][F3] respectively

1. CLEAN THE SLATE (so to speak) and ENTER DATA

In Home folder run F6: NewProb to reset the configuration.
Press Apps, and select 6: data/Matrix editor. Select a new data set


Give it a name: here testing.



Press OK/ENTER, The data entry screen opens, enter your values.


When you finish press F2.PlotSetUp.

2. Statistical plot setup and scatter plot drawing

.

Press F1:define to configure Plot1. Choose Scatter, then choose a mark for the data point. I select 5:Dot. and press [ENTER


Select the data column X=c1, Y=c2



Press ENTER to save configuration. Press [CTRL] [GRAPH] On my TI92 the CTRL key is the [Diamond] key. On the following graph I changed the mark to a cross to see the data point better. I also played with the window dimension. You can also do that with ZoomStat. The graph remind me of a parabola (I know I chose the exact values)



3. STATISTICAL CALC. AND REGRESSION ANALYSES.

Now we have to find the equation that fits these data best.
You press APPS 6:Data/ Matrix editor but you select current to return to your data set. You are taken to the data entry editor (Figure 3 above). In that screen Press F5:Calc to edit the type of statistics you want

On first line select the type of regression model : Linear Regression, QuadReg quadratic regression (or anything else available) X is from column1, Y is from column 2. Store RegEQ The regression equation in say Y1(x)



Press ENTER to save to get the Regression Equation. Here it is
As you can see I cheated: a perfect parabola. R^2 =1.



And here the best fit represented on same graph as the statistical data



Usually you have to try different regression models, until you find the one that fits best the experimental data.

Upgrade the OS of the calculator to the 2.53 MP (Math Print) version. As you can see on the following screen capture of the MODE setting, you can choose to use the CLASSIC option (the old way) or the MathPrint version.
You should notice that the Answers AUTO DEC or FRAC options allow you to configure the calculator to work in DECimal, FRACtions or AUTO (the calculator chooses whats is appropriate).
The n/d is for improper fractions and Un/d for mixed fractions.

Enjoy your new found freedom.



Here is the link to the new OS 2.53MP

The calculator has two input/output (I/O) modes: MthIO and LineIO.
MthIO is a very nice novelty: it allows one to enter expressions as with pen and paper (textbook display). Results are displayed, whenever possible, as exact values ie fractions and radicals.
MthIO is the default I/O mode of the calculator. If it is not set, you can set it by pressing [SHIFT][MODE] (SetUp) to access a list of choices. Select [1:MthIO].

The other I/O mode is the old way of doing things: every thing is enter on the same level line, while in MthIO you have textbook style templates. In LineI/O all results are displayed as decimal (approximate) values.

To set LineIO press [SHIFT][MODE](SetUp) and select [2:LineIO].

If the displyed result is fresh you can toggle between decimals and fractions/radicals by pressing the [S<=>D] key.
Even if you are in MthIO you can force the (final) result into decimal display format by pressing, NOT the = sign, but [SHIFT][=] .

This is my first post on this site, but I've had friends at school ask me about this. Apparently I'm like a calculator genius or something...

One solution I know of is clearing the RAM. Sounds strange, doesn't it? But it fixed three different calcs.

Be sure to back up or archive important data before doing this.

probly because the calc was miscalibrated or someone screwed around with the variables...
hope this helps