To demonstrate a price change on a graph, a point on the demand curve is moved to represent the new price and quantity demanded. A price decrease from $6 to $2 would typically result in an increase in quantity demanded, and it's shown by moving the point down and to the right along the curve.
The student's question involves moving a point along a demand curve to showcase the effect of a change in price. Specifically, the student needs to understand how a price drop from $6 to $2 would be represented on a graph. To illustrate this using the given information, imagine a demand curve on a graph where the vertical axis represents price and the horizontal axis represents quantity demanded (Qd). As the price drops from $6 to $2, you would generally expect the Qd to increase, according to the law of demand. This movement would be visually represented by dragging the point along the demand curve downward (to indicate a lower price) and to the right (to indicate a higher quantity demanded). The provided chapters also touch on the concept of a shift in the demand curve, explaining that an increase in income can cause an upward (or rightward) shift in the demand curve, which means at any given price, the quantity demanded would increase.