The First of Many Shortcuts
To get around the problem in the previous activity, we're going to take a short cut with Geogebra. Geogebra has a tool built in for calculating the line at the limit of the secant lines. The line at the limit of the secant lines is called a tangent line. We'll define it precisely in the next activity. For now, we're only going to see how Geogebra can calculate them for us..
The built-in tool in Geogebra for finding tangent lines is called "Tangents" and the icon looks like this: 
Hunt around in the drop down menus for the Tangents tool, and use it to create the tangent line to
Hunt around in the drop down menus for the Tangents tool, and use it to create the tangent line to f(x) at A. When you select it, it should provide you with instructions about how to use it. If not, leave your mouse hovered over the Geogebra tool for a quick set of instructions on how to use it. The key thing to know is that the tangent line to a function
f(x) at a point A like above is the limit of the secant lines at A as h tends to 0. Go back and review the chapter on limits if you need to! By using this tool in Geogebra, we're taking a huge shortcut and letting the computer take care of calculating a pile of limits all at once. Pretty impressive. Move ahead to continue studying tangent lines.