Every time i try to graph a function "undefined variable" pops up on the screen and then i can't get anywhere after that

You might have used an inappropriate variable name.
For functional graphs y=F(x), the independent variable must be X
For parametric graphs, the independent variable in the x_t and y_t functions must be t.
For polar graphs the independent variable must be Theta, and for sequence graphs, it must be the special wiggly n.
Once you select the type of graph, the independent variable is entered by pressing the key marked X,T, Theta, n.

Error 14 undefined may occur if you are referencing a variable that currently is not defined

At first type next: Home, then 2nd F6: 2 option NewProb.
Then graphing function, for example y=-x^2+28x+6

From the alpha keyboard type in NewProb and press ENTER.
This will clear the contents of all the one-letter variables a-z.
Open the Y= editor and type in an expression for the function to draw.
You do not have to enter a multiplication sign between a numerical factor preceding the variable x and x. If a factor is a letter you must explicitly use the multiplication sign.


Press the key sequence to draw the graph.

When you graph functions y=f(x), even if f(x) is a trigonometric function, the default independent variable is x. You will have to use the variable theta only when drawing polar functions.
To draw the sine and cosine or any other trigonometric function set the angle unit to radians and window zoom to standard. If your angle unit is degree you must modify the x-window range to, say, multiples of 180 degrees. Other than that there is nothing special to do. The functions are well-behaved and should graph nicely. You will alos get a better view if Ymin is about -1.2 and Ymax is about 1.2

If you want to graph the absolute value of a function, feed the function to the absolute value ie graph y= abs(f(x)). The calculator will take care of it. See screen captures where I draw the function y1=x^3-5x^2-3 and y2='x^3-5x^2-3'. On the first graph the function is represented and on the second the function and its absolute value.







The calculator knows how to calculate the absolute value of an expression. The name of the command is abs(

Hello,
The default variable for the integral is x. If you have a product between two litteral symbols the * must be inserted. Arguments of functions must be enclosed between parentheses. To avoid errors clear the variables before the integration: [2nd][F6:Clean Up] [2:NewProb][ENTER]ENTER]



Hope it helps.

That means one (or more) of the variables you have in your function is not defined. Check to make sure you didn't misspell any variable name. Also, check to make sure you didn't run two variable names together. "ab" is the variable ab, not a times b.

Hello,
I have a manual in another language than English, so I do no know exactly or remotely what procedure you refer to, but I have recreated an instance where one gets the error you talk about. I give you the picts. When I enter [Diamond][Graph] I get the following message.

The graph independent variable is x by default, yet I entered cos(f). The calculator is expecting a function of x and I give it a function of some as other entity. Hence the error message. On the command line you cannot change the argument of Y1. It is x by default.

Hope it clarifies things.

go to home and type Define x