Question about Texas Instruments TI-83 Plus Calculator

# When I'm entering a quadratic function, I'm getting the graph of something that is not a parabola like it should be. However, when I graph x^2 by itself, it looks the way it should. What can I do to fix this?

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• Texas Instru... Master

The actual graph depends on the constants (parameters) that are in the equation. Try playing with the dimensions of the window by zooming in or zooming out.
The most interesting part of the graph is the region near the maximum or minimum.
Here is a graph of the function y=X^2-5X 13 when drawn with standard window dimensions

Not very revealing. However if you press the Zoom key and select [2:ZoomIn] you see this (no changes) but the calculator is ready to accept your input concerning the new center of the graph.

At this stage, use the Arrow keys to move the center of the graph to another point as in the neWhen I'm entering a quadratic function, I'm - 0e09736.jpgapture.

Notice the new center as a sign on the screWhen I'm entering a quadratic function, I'm - fc695b8.jpgcoordinates at the bottom. By pressing [ENTER] you get this

If you keep Zooming in you may end up having something that does not look like a parabola anymore.

To summarize: Use the Zoom In or Zoom Out functions or find where the minimum/maximum is, center the graph on that point and modify the windows dimensions (Xmin, Xmax, Ymin, and Ymax) so as to get as much of the interesting part of the graph as possible.

Posted on Sep 06, 2010

• k24674 Sep 06, 2010

I do not what what this site has against the plus ( ) sign, but it clipped the plus in the equation y=X^2-5X plus 13.

×

Hi,
a 6ya Technician can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repair professionals here in the US.
Goodluck!

Posted on Jan 02, 2017

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## Related Questions:

### Minimum or maximum values of a parabola

Follow these steps: graph the parabola and after that 2nd then CALC keypad. To find extreme value of the function select 3: min or 4: max options. Select the function and set left bound, right bound(using left and right arrows) by pressing ENTER. You can see images bellow for all these steps for the y=-2x^2+5x+3

1. step: graphing parabola

2. step: left or lower bound

3. step: right or upper bound

4.step: extreme value of the function

Mar 08, 2012 | Texas Instruments TI84PLUS Slvr Viewscreen...

### Minimum or maximum value of a parabola

Follow these steps: graph the parabola and after that 2nd then CALC keypad. To find extreme value of the function select 3: min or 4: max options. Select the function and set left bound, right bound(using left and right arrows) by pressing ENTER. You can see images bellow for all these steps for the y=-2x^2+5x+3

1. step: graphing parabola

2. step: left or lower bound

3. step: right or upper bound

4.step: extreme value of the function

Mar 08, 2012 | Texas Instruments TI-84 Plus Silver...

### My fx-9750GA PLUS wont graph lines, cicles or paraballas

To draw functions (regular, parametric, polar, sequences) use the application graph: Highloghted on 1st screen capture. The second screen captures shows you the functions y=f(x). enter a legal expression and press F6 Draw. To set TYPE press the key under TYPE.

To draw conics (circles, parabolas, hyperbolas, and ellipses) use the CONiCS applications. (See 3rd screen ). On 4th capture the equation highlight is one for the parabola. y=x^2

Scroll down or up examining the small graphs. They will show you which equation form to choose.
For the circles

Jun 19, 2011 | Casio FX-9750GPlus Calculator

### I am trying to do a project and i need to find the sine regression on the TI-84 PLus Silver Edition calculator. Can you please tell me how to do that?

Here is a copy on an earlier post I made detailing how to do a regression on a TI8x Plus families of calculators. In the post I took a quadratic regression, but that should not be a problem for you to use the same techniques. Just, when you reach the point where you select the regression model, select SinReg.
If you follow the instructions you should be able to get the scatter plot and the best-fit curve on the same graph. If you do get an error check your data and blame not the method I will show you because it is sound.

Here it goes
Your question is a very interesting one and I believe people will benefit from a complete solution to it. So I will provide a solution for a quadratic regression.
The points I will represent are those on a parabola
L1= {0,1,2,3,4,5,6,7,8,9,10}
L2={0,1,4,9,16,25,36,49,64,81,100}
As you can see, I am cheating (no experimental points will fit a perfect parabola) but this will have no incidence on what I am going to show you.

1. PREPARE THE GRAPH FORMAT (you will see why latter)
With the calculator turned On, press [2nd][ZOOM] to access the (FORMAT) screen. Notice that RectGC is highlighted. It means that the coordinates are rectangular. IF the POLARGC had been highlighted and you had used the TRACE function the values of the coordinates of the points being traced would be in the form (R, theta), in other words polar coordinates.

2. ENTER THE DATA

Press STAT, then under the EDIT menu press [1:Edit]

to open the list editing screen. Enter the elements of the two lists

After you enter the data in L1 and L1, Press [2nd][Y=] to open the (STAT PLOT)

3. CONFIGURE THE STAT PLOT TYPE

Initially the Plot1 may be OFF. Make sure at the beginning that all Stat Plots are OFF. If necessary press [4:PlotsOff] execute the command in Main calculator screen and press [2nd][Y=1] to get back at the stat plot screen configuration below

Press 1:Plot1 Off to open the P1 configuration
The cursor will be blinking on On. If not use cursor to highlight ON and press [ENTER]. The cursor will move to second line (TYPE), on first icon. Since you want to do a scatter PLOT that is the one to choose. Highlight it and press ENTER then move cursor with Down arrow to move to Xlist
If your data is in L1 and L2 Xlist and Ylist will be already selected. If you have entered your data in some other lists, enter the proper lists (L3,L4, etc.)

DRAWING THE SCATTER PLOT

Now you can press the [GRAPH] function key. Here is what you get

PERFORMING A REGRESSION

Because I chose it so, we will perform a quadratic regression QuadReg
To do so you press [STAT] and use right arrow to select the CALC(ulate) Menu. Type 5:QuadReg

Command echoes on Main screen as QuadReg with blinking cursor as above on the right.

If you press [ENTER] the calculator will assign L1 to X and L2 to Y by default. If that does not correspond to the problem, you had better change the names of the lists used by entering then explicitly on the command line. Just press [2nd][L1] then [2nd] [L2] to get the following screen

Pressing [ENTER] to execute the command will get you the regression equation and its coefficients but you will not be able to have it graphed on the scatter plot

The coefficient/factor of determination R2 is displayed if you ran the DiagnosticOn command from the catalog, or as in the newer version of the OS (version 2.53MP) you press [MODE], scroll down to get to the second page of options and selected Stat Diagnostics ON

Thus to be able to draw the regression curve on the scatter plot, you must save it to a function variable, Y1 for example. You do it with the following command line

After you press ENTER you obtain the equation, a,b,c, and R2. By pressing the [GRAPH] function key you get the raw data and the regression on the same screen.

As you can see both are represented

TRACING THE REGRESSION CURVE
Press Trace and see what you get

As you can see the trace defaults to the scatter plot P1, L1,L2 (see the top left). If you stay on that graph you will on ly trace the actual data points (raw data). The cursor will jump from one point to the next.
To trace the regression curve (the second curve) you must move cursor on it. To do so press the Up and Down arrows. Left and right arrows allow cursor to move along the same curve.
Pressing Down Arrow you move to the regression curve. Notice the equation on the top left corner. The cursor can be displaced anywhere (depending on the resolution of the graph.

If you want Y for a particular value of X, just enter the value of X
Enter an X value. How about 5.55555?
Type in the value and press [ENTER] et voil?.

If as I have suggested above, you copied the regression equation to Y1 variable, you can calculate Y-values for any X in the graph domain.

In Main calculator screen type the numerical value of X, say 4.777756, and store it in X-variable

4.777756 [STO>] [X,T,theta,n] [ENTER]

Press [VARS][>][Y-VARS][1:Function...][1:Y1] [ENTER]

The calculator computes the value of Y1 for the entered value of X.
You can also generate a whole table, but you will have less control over the points where Y1 will be calculated.

Feb 13, 2011 | Texas Instruments TI-84 Plus Calculator

### TI-83 graph problems-help please. Hi, sorry to sound so stupid, but trying for hours to try to solve these using my calculator,but doing something wrong as can't get the right answers. I wonder if anyone...

Parabolas
Open Y= editor and type in the two functions

The calculaus functions are accessible by pressing [2nd][TRACE] to open the CALCulate menu options. For the gradient (I think you mean the derivative) use option 6:dy/dx. But first choose the point where you want it calculated (use cursor to move along the curve) and press ENTER. The value of the deivative will be calculated at the chosen point.

The vertex of the parabolas are maxima. Thus you must use option 4:maximum

You will be prompted for a left bound. Move cursor to the left of the maximum (not too far) and press [ENTER]. A fat arrow is displayed on the graph that shows the left limit of the interval. You will be prompted for a right bound. Move cursor along the curve to the right of the the vertex. Press ENTER. A seconf fat arrow will be displayed to show the right limit of the interval.

You will be prompted for a guess of the maximum. Move cursor newar the max or enter a numerical value and press ENTER.

The location of the vertex is displayed (X and Y values)

I have no idea what you mean by the equation of symmetry

Intercept.

May 02, 2010 | Texas Instruments TI-83 Plus Calculator

### Find the equation of the line that best fits on a ti 89 calculator

Hello,
I assume you know how to enter data in your calculator.
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.
.

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. Th graph remind me of a parabola (I know I chose the exact values)

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 QuadReg quadratic regression, 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 Equatio. 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 satistical data

Usually you have to try different regression models, until you find the one that fits best the experimental data.
As you can see I have gone a long way out of my way to show you all the steps.
I hope it helps you and others who wonder how to do regressions on a TI89. If someone does not understand these explanations, the blame does not rest with me.

Oct 21, 2009 | Texas Instruments TI-89 Calculator

### How do I graph parabolas?

Parabolas are forms of the base equation X^2. So press the [Y=] key, and then type in the variation of x squared that you want

May 11, 2009 | Texas Instruments TI-83 Plus Calculator

### Functions?

Hello,
I am afraid I am missing something here. You can start with the expression of a function and have it graphed on a graphing calculator.
Or you can enter the experimental data, represent them on a graphing calculator and ask the calculator to find the curve that fits the data best, and once that curve is found to give you the equation.
However your calculator does not have the graphing capabilities. All you can do is enter the data and ask the calculator to perform a regression to obtain the expression of the function that fits best.

The available options for the calculator are accessible by pressing [MODE][3:Stat] and
2. A+BX linear
4: ln X logarithmic
5: e^X exponential
6:A*B^X power
7: A*X^B Polynomial
8: 1/X

Hope it helps.

Apr 14, 2009 | Casio fx-300ES Calculator

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