You can use an alternative method to graph a function on the TI-Nspire. Before doing so, insert a new Graphs page by pressing [DOC]→Insert→Graph or press [CTRL][I]→Add Graphs. You also can press [CTRL][G] to hide the entry line.
Here's how to perform an alternative method to graph the function y = 0.2x4 – 2x2:
Move your cursor to some open space and right-click by pressing [CTRL][MENU]→Text to open the Text tool.
Type 0.2x4 – 2x2 and press [ENTER] to close the text box.
Press [ESC] to close the Text tool.
Grab (press [CTRL][CLICK]) and drag the text expression to the x-axis and notice that a ghosted image of the graph appears. Press [ENTER] to graph this function.
You should approach the x-axis very slowly for this method to work. The sequence of screens shows how this method works.
Move back to the expression y = 0.2x4 – 2x2 that is automatically placed on the screen. Press [CLICK] twice to allow editing of the equation, and press [ENTER] to put your changes into effect. Any changes that you make are automatically reflected in the graph. If the entry line gets in the way, press [CTRL][G] to close it.