Let's examine the demand for videocassette recorders (VCRs), which can be affected by their own price as well as the income of consumers and the price of a competing good, the DVD player.
Use your mouse to drag the green line on the graph. The values in the boxes on the right side of the calculator will change accordingly. You can also directly change the values in the boxes with the white background by clicking in the box and typing. The graph and any related values will change accordingly.