Back to Help with TI-Nspire
Entry line
The Entry line appears at the bottom of the Graphs & Geometry work area:
When the line is not active, it is grayed out. From left to right, the parts of this line are:
Hide/Show function button.
Attributes button.
f1(x)= is the default notation used for a function or inequality.
Blank area into which you enter the function, polar equation, inequality, parametric or scatter plot data to be graphed.
Expand/Contract (History) button.
Parametric Mode entry line. The default values for t-min, t-max, and t-step are shown.
Scatter Plot Mode entry line
Polar Mode entry line
Using the entry line
To enter a function on the entry line:
- Select the mode.
- Type the function you want to graph in the space at the right of the = sign.
- Press
or 
.
You can enter and graph a maximum of 99 functions on the screen (f1(x) - f99(x)) in addition to any user-named functions such as g1(x). You can review the functions entered on a page by pressing the Expand button.
Use 
and 
to move up and down the list.
You can also graph functions by typing them into a text box:
- Select the Text tool (
), and type the function you want to graph into the box displayed when you move the cursor onto the page. - Drag the text box to the x-axis, and drop it on the axis to graph the function.
Regardless of how you enter functions, each function is labeled on the graph for identification.
Graphing inequalities
Function mode enables you to define a function that uses a symbol other than the equal sign. To change = to a different sign and graph the inequality:
- Position the cursor to the right of the equal sign. Press
to delete the equal sign. - Type the desired sign or use the Symbol Palette to enter the appropriate inequality. The possible inequalities are: >, <, ≤, and ≥.
- Type the rest of the inequality expression. Press to graph it.
The expression, as typed, displays next to the graph. Shading is always present on the graphs of inequalities to show the values that satisfy the inequality. If you graph two inequalities that overlap, the area of overlap is shaded darker than either of the individual inequality graphs.
Finding points of interest: zeroes, minima, maxima
When you create a graph, you can use the Point On tool (
) (press 
) to locate the zeros, minima, and maxima if these are applicable for objects on the work area. (They may not display if their location on the graph not visible on your screen.) Both local and global points of interest display.
Note: Global points of interest display only when they are also local. For example, inverse sine reaches its (global) maximum at x=1, but the tooltip 'M' does not display there since it is not a local maximum.
To find them, just move the point along the object or graphed line, and when you are near a point of interest, the coordinates display along with one of the following identifiers:
- Zeroes: z ( Coordinates )
- Minimum: m ( Coordinates )
- Maximum: M ( Coordinates )
Follow along with this example to graph an equation and find the points of interest.
First, open a new document. To do this press 
. Use the navpad to select Add Graphs & Geometry from the menu to open a Graphs & Geometry Application.
Enter the equation into the Entry Line.
Now press 
.
You may wish to hide the Entry Line. To do so press 
.
Now you have graphed the equation.
The next step is to use use the Point On tool to locate the zeros, minima, and maxima.
To use the tool, press .
Use the navpad to guide the cursor to a point on your graphed function and click on it.
Now you have a point on your graph.
Press esc to exit the tool and use the navpad to drag the point along the curve until you get close to a point of interest.
One such point is shown.
Zeroes: z ( Coordinates )
minimum: m ( Coordinates )
Maximum: M ( Coordinates )
Your points of interest rounded to the nearest hundredth should be:
z: (-2.37,0);(-1.20,0);(0.23,0)
m: (-0.36,-3.00)
M: (-1.86,2.13)