Final answer:
Demand for personal computers can be affected by a rise in income, expected prices, software costs, and usability, all of which shift the demand curve to the right or left in a supply and demand diagram. Recently, an increase in computer sales at lower prices could be due to an increased supply or demand, typically illustrated by a shift in the respective curves.
Step-by-step explanation:
To describe how various factors affect the demand for personal computers, we can reference the law of demand and how demand curves shift in a supply and demand diagram. For example, when incomes rise and assuming computers are a normal good, more people will be able to afford them, leading to an increase in demand. This shift can be represented as a rightward shift in the demand curve.
Similarly, a lower expected price for computers in the future can make customers wait, reducing the current demand, which is depicted as a leftward shift of the demand curve. Conversely, factors like cheaper software or an increase in the ease of use of computers would increase the demand, creating a rightward shift.
When considering how a market reacts to such demand shifts, it typically involves a change in both the quantity and price of the goods. For instance, in the computer market, an increase in sales at lower prices could be a result of either an increase in supply or an increase in demand. If the market experiences an increase in supply, for example due to technological improvements, this would be shown as a rightward shift in the supply curve, leading to a larger quantity of computers being sold at lower prices.