When I enter a function in Y1 and Y2, my calculator only graphs y1. How can I see both functions?

All graphs, except the linear function y=ax+b, are non-linear. To graph a function, just enter the GRAPH utility, type in the functions Y1=, Y2=, ... and press the Draw tab.
If you have a specific question, ask it.

When you push the button [Y=] to open the function editor you will see Y1=,Y2= etc. That is the default behavior. By default the graph type is FUNCTION (y=f((x). However there are other graph types, for instance PARAM, POLAR, and SEQUENCE.
For Parametric graphs, you need two functions x as a function of t and y as a function of t. In this case, when you open the function editor, you will see pairs of functions x1(t), y1(t), x2(t), y2(t), etc. Both x and y functions of the pair must be supplied.

So if your x= function is not showing, then you must open the MODE screen, and scroll down to reach the 4th line that says FUNC, PAR, POL, SEQ. Highlight PAR and press ENTER. You do that only if you want to graph parametric functions.

To graph a f o g problem input the g function for y1. Then for y2 input the f function, anywhere there is an x (or whatever your variable is) put y1 instead.

The presence of the Fat arrows to the left of the Y1, Y2,etc = functions means that the Transfrm application is running. It takes over the graphing from the native OS.
You must uninstall it.

1. Press [APPS] and scroll up to go to the bottom of the list of Applications.
   
2. Highlight [ : Transfm] and press [ENTER]
3. In the new screen with the heading "Transfm App" press the number that corresponds to uninstalling the Apps [1:Uninstall]
4. Try to graph two simple functions Y1=X and Y2=2X.
5. If these functions are graphed correctly you are back in business, if not turn Stats Plots off.

To turn Stat plots Off
Press [2nd][Y=] (Stat Plot)
Press [4:PlotsOff]
Press [ENTER]

If all else fails, Reset the Ram
Press [2nd][+] (MEM)
Press [7:Reset]
Press [1:All Ram]
Press [2:Reset]
Press [ENTER]
Press [CLEAR] to erase the "Ram Cleared" Message.

Let us see if I understand what you want to do. You have two functions f and g. With f and g you create four functions,

1. f+g, which you want to evaluate at 0
2. f-g, which you want to evaluate at -1
3. f*g, which you want to evaluate at 1
4. and f/g, which you want to evaluate at 3

If that is not what you intend to do, then I am sorry to I that interpreted incorrectly and you will have to post a comment with more information.
If however I did understand what you want to do, then there is a simple way to achieve this

1. In the [Y=] function editor, enter Y1 and Y2
2. In your mind decide which one represents f(x) and which represents g(x), probably f(x)=Y1(x) and g(x)= Y2(x)
   
3. Validate each one by pressing [ENTER]
   
4. Do not worry about graphing the function.
5. Press [2nd][QUIT] to return to main calculator screen
6. Enter a value (for example 5) and store it in variable X; to do so you press 5 [STO->][X,T, theta,n] [ENTER]
7. To calculate f(x)+g(x) or (f+g)(x) on the command line in main calculator screen

• Press [VARS][=>][Y-VARS][1:Function][1:Y1][ENTER]. Main calculator screen echoes Y1
• Press [+]. Screen shows Y1+
  
• Press [VARS][=>][Y-VARS][1:Function][1:Y2][ENTER]. Main calculator screen echoes Y1+Y2
• Press [ENTER] to obtain the value of f+g at X=5
  

As you can see, if you want a different operation f-g, f*g, or f`/g for a different value of X, you will have to repeat steps 6 and 7.

I am going to show you how to create a small program that will perform all the 4 operations in sequence, each time asking you for the value of X you want to use. If you are not interested, you can ignore what follows. I remain convinced that it will be helpful for other visitors.

Creating a simple program

Press [PRGM]
Use arrow to highlight [NEW]
Press [ENTER]
Screen displays
PROGRAM
Name= with alpha cursor blinking
Type in the name, for example FOPG ( meaning F operation G) or anything else. Do not use a keyword (reserved command of the TI84Plus) These are what you find in the [CATALOG].



The top line on each screen capture is inserted by the program editor after you choose the name. The last line of first screen is the the same line as the second line on 2nd screen. It must not be entered. The colon : is supplied by the program editor. It is the beginning of an instruction.

There are only to commands that are repeated here: Disp and Prompt

Disp orders the program to display

1. a message (what is between the quotation marks) or
   
2. the result of a calculation: Y1+Y2, Y1-Y2, Y1*Y2, or Y1/Y2

Prompt X will display X=? and the blinking cursor. You are supposed to enter the desired value of X and press [ENTER].
The Disp and Prompt command are accessed through the command catalog by pressing [2nd][0] (CATALOG) then scrolling along the list of commands to find the one needed. Shortcuts are possible (see below)

How to key in the program steps within the program editor
: Disp "F+G"

Press [2nd][0] (CATALOG) [X^-1](D) [Scroll Down [till...] Disp
Press [ENTER]. Editor shows :Disp
Press [ALPHA] [+] ("). Editor shows :Disp "
Press [ALPHA][COS] (F). Editor shows :Disp "F
Press [+]. Editor shows :Disp "F+
Press [ALPHA][TAN] (G). Editor shows :Disp "F+G
Press [ALPHA][+] (") Editor shows :Disp "F+G"
Press [ENTER] to validate instruction
Calculator inserts a new line :

: Disp Y1+Y2
Press [2nd][0] (CATALOG) [X^-1](D) [Scroll Down [till...] Disp
Press [ENTER]. Editor shows :Disp
Press [VARS][=>][Y-VARS][1:Function][1:Y1][ENTER]. Editor shows :Disp Y1
Press [+] . Editor shows :Disp Y1+
Press [VARS][=>][Y-VARS][1:Function][1:Y2][ENTER]. Editor shows :Disp Y1+Y2
Press {ENTER] to validate instruction
Editor inserts a new line :


:Prompt X
Press [2nd][0] (CATALOG) [8](P) [Scroll Down [till...] Prompt
Press [ENTER]. Editor shows :Prompt
Press [X,T.theta,n] key. Editor shows :Prompt X
Press [ENTER] to validate instruction
Editor inserts a new line :

To save program
Once all instructions are entered, press [2nd][QUIT] to save program.

To run program

1. Press [PRGM]
2. Under the [EXEC] menu, the list of available programs appears.
3. Type the number corresponding to the one you want to run ( FOPG) and press [ENTER].
4. The main calculator screen displays prgmFOPG and blinking cursor.
5. Press [ENTER] to make it run
6. Enter a value of X and press [ENTER]
7. Follow instructions.

Hi,
The TI84Plus has a Shade( function which allows you to represent the area you want to calculate.
The simplest syntax of the command is

Shade( lower_function, upper_function, Xleft, Xright, pattern, patern_resol) where Xleft is the left limit, Xright is the right limit, pattern is the shading pattern and pattern_resol is the resolution of the shading. Only the area where lower_function is less than upper_function is shaded. Unfortunately this command does give the value of the shaded area.

To find the area between two curves

1. Draw the curves
2. Find the left intersection point using [2nd][CALC][5:intersect]. Sorry I will not describe the procedure. The X value of the intersection point is stored in Ans memory.
3. Press [2nd][QUIT] to go to main calculator screen.
   
4. Store the Ans result in say A: [2nd][Ans][STO->][ALPHA] A
5. Return to the graph by pressing [GRAPH].
6. Find a second intersection point. Result is stored in Ans memory.
7. Press [2nd][Quit] to return to main calculator screen
8. Press [2nd][Ans][STO->][ALPHA] B to store the X value of the second intersection point in B.
9. Use the CATALOG to paste the fnInt( command to calculate the integral : [2nd][CATALOG][[APLHA] F and scroll to select fnInt( and press [ENTER]
10. To complete the command you need the identifiers Y1 and Y2.. You access the identifiers Y1 and Y2 by pressing [VARS][Y-VARS][1:Function][1:Y1] and [VARS][Y-VARS][1:Function][2:Y2]
11. The command should appear as fnInt( Y2-Y1,A,B)
12. Press [ENTER] to obtain your value.

Hope it helps.
Thank you for using FixYa.
Do not forget to rate the solution.

Hello,
If I understand correctly you want to use the graph function Y1, or Y2, ..in an equation. In the [RUN] screen press [VARS][F4:GRPH][F1:Y]. It echoes on the screen as Y. Press 1 and you have Y1.
However, you will not be able to manipulate it symbolically, because that variable contains the value of Y1 for X=0, if you have not drawn it yet. or tha value of Y1 for the last X used to draw the graph Y1=f(X).
The calculator is not capable of manipulating symbolic expressions. what you want it to do is beyond its capabilities.

Hope it helps.

To view both graphs, the = signs on both y1 and y2 must be contained in black boxes. If you put your cursor over the = sign on the second equation and hit enter, it turns that graph off and you won't be able to see anything but the equation in y1 line. If there is not black box around the = sign of any equation in any of the lines you have typed an equation into, you will not see the graph.

Hello,
Here how you do it taking as exemples y1=x^3 -5 and y2=abs(x^3-5)
Turn calculator ON by pressing [AC/On] . Use arrows to select [Graph] icon and press [EXE]
On line Y1= enter X[^]3 -5 [EXE]
On line Y2= press [OPTN] [F5:NUM][F1:abs] [(] X [^]3 -5 [)] [EXE]
The graphs will be drawn one after the other. You might have to adjust the window limits.
Here is an ouput drawn on another calculator.

For negative values of the x-variable, Y1 has negative values, while in the same range, Y2 has positive values, equal and opposite to those of Y1. In that range, Y1 and Y2 are symetric of each other with respect to the X axis.
For positive values of the x-variable, Y1 and Y2 are identical.

Hope it helps

Hello,

It is actually quite simple. The calculator can perform severa types of graphing, but the most common is the drawing of functions defined by a relation of the form y= fonction(x), or y=f(x) for short.

The procedure is described for the TI 89 Titanium. It is valid for the TI 89 except if I enter the color of a key.
1. Before you start, you should set up the calculator to begin a New Problem. The command for that is accessed through the menus.
Press the [HOME] key to go to main calculator folder.
In Home folder, press [2nd][F1] to access [F6][2:NewProb]. Press [ENTER] to execute the command. Screen should display Done.
2. Press yellow [Diamond] key (it is the equivalent of the CTRL key in computers) then [F1] to open the [Y=] editor.
3. Use the keypad to enter your first function on Y1= line. Press [ENTER] when finished with Y1. This will select the curve to be drawn, and a check mark appears to the left of the Y, in Y1=. If there is no check mark, the curve will not be drawn. If that happens, move cursor on Y1= and highlight it and press ENTER.
4. Enter the next function. Press [ENTER] when finished.

Try the functions Y1=3*x+0.5 and Y2=x^2 -1.

5. Press the yellow [Diamond] key to access [GRAPH]. The cartesian screen appears, the calculator starts graphing. While graphs are being drawn, the indicator BUSY is displayed at the bottom of the screen, on the right.

Here is what your screen looks like.

6. If BUSY indicator disappears, graphs are finished. If nothing is displayed on the screen except the axes, the functions may be out of range. In that case you can adjust the window dimensions.


You can change the values of Xmin, Xmax, Ymin, Ymax, or press [F2:Zoom] to use any of the zooming options.

This is the basic procedure to draw y=f(x) graphs.
Hope it helps.