This applet is designed to build the intuition between the idea of a derivative being the slope of the line tangent to a curve and the idea of a derivative as a function symbolically computed from the formula of the original function. The viewing window gives the graph of a function, a point on the graph, the tangent to the graph at the point, and a point the slope into the height of a point. The window also graphs a guessed derivative for the function. This is one of many GeoGebra applets in Mike May's GeoGebra Applets collection at http://www.slu.edu/classes/maymk/GeoGebra/.