This applet will allow you to explore secant and tangent lines. Type whatever function you want into the box for f(x). Use the ^ key to enter in exponents just like you would on most graphing calculators. It works best if you use a function that fits in the given viewing window. If you have to change the viewing window, some of the controls will move too.[br][br]If you click on the box next to Secant Line, a red secant line that connects two points on the graph of the f(x) will appear along with the equation of that line. The sliders c & d can be used to change the two points.[br][br]If you click on the box next to Tangent Line, a blue tangent line will appear along with its equation. The slider c can be used to move the point at which the line is tangent to the graph.