The spreadsheet is not essential, but it might be valuable to present the cost function in a linked numeric form.

1. Open the spreadsheet by View > Spreadsheet

2. Drag the window edges so that you can see the Wolfe Island image in the Graphics 2 window, the graph from x=0 to x=3 in the Graphics window, and columns A and B of the spreadsheet. To assist in this you could remove the Algebra window by clicking View > Algebra. You may also need to Zoom out on the Graphics 2 window to get the full image. 

3. Put the point P in the (0,#) position by dragging the shore point in the Graphics 2 window. Remove the trace by View > Refresh Views

4. Right-click point P and in the pop-up window click Record to Spreadsheet. In the second pop-up window click Clear all traces and Close

5. Drag the shore point and observe the graph and spreadsheet

6. Restore the learning object to its starting position by:

• Return point P to the (0,#) position
• Clear the curve trace by View > Refresh Views
• Clear the spreadsheet data by repeating 4 above.

7. Save your GeoGebra construction

Your GeoGebra software should look something like the image below. If you are having difficulties you can click on the image and open or download the GeoGebra file.