Demand and Supply for Computer Softwares...

Supply--Assumption:
1) NO variable cost e.g. delivery costs, admin costs etc
2) some amount of fixed cost e.g. cost of original copy, R&D of the software etc

Supply--Curve:
Horizontal line above the zero cost

Demand--Curve:
Normal demand curve but not horizonal coz higher the price of the software, lower the quantity demanded. The demand curve isn't affected why how the softwares are supplied.

唔會係同一條curve,
因為Supply curve其實代表生產每一個quantity既cost,
只有price係supply curve之上先會被生產

而家既然作係sell softwares online.
咁marginal cost係zero
所以supply curve應該係horizontally lies on X-axis

上面果位話因為有fixed cost,
而應該係above zero其實唔係好岩
因為fixed cost係sunk cost
係已經比左出去，生唔生產都係咁多
所以係唔會影響生產既decision
所以唔會反映係supply curve度

所以... MC = 0, Supply curve lies on X-axis

而Demand curve就係普通downward sloping
因為Law of Demand...
full price and Qd are negatively related, other factors being constant