Derivative of sin(2x)

Find the derivative of sin(2x) graphically

Drag Point P across the graph of y=sin(2x) 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?