Derivative of sin(x)
Find the derivative of sin(x) graphically
Drag Point P across the graph of y=sin(x) and observe the gradient of the red tangent line. Plot the gradient in the bottom graph at intervals of /2. Drag Point P back to the start, tick the Show Q checkbox and watch Point Q trace out the gradient of the tangent as you again drag Point P across. Did the tace go through the points you plotted?