Why does monopoly need to be regulated?

An example of a monopoly could be: a. the only veterinary doctor on an island b. a big hospital in a big city c. a big city restaurant d. the hotels in san juan

How to calculate profit or loss in monopoly market ??

DeBeers has a monopoly on the production of diamonds. Use the following graph showing the demand, MR and cost curves of DeBeers to answer the questions below. How many carats of diamonds does DeBeers produce to maximize its annual profit? What price does it charge? How much annual profit does it make? If DeBeers was producing at the allocatively efficient level of output, how many carats of diamonds would it produce? What price would it charge? Suppose that the government decided to regulate DeBeers monopoly and imposes a price ceiling of $50 per carat of diamonds. How many carats of diamonds would DeBeers produce? What price would it charge? What profit would it make?