ECO2030 1st Edition Final Exam Study Guide Lectures: 29 - 33 ● Total Revenue amount a firm receives for the sale of its output (QxP)● Total Cost  the market value of the inputs a firm uses in production (materials, labor,rent, etc)● Profit total revenue minus total cost○ Know difference between revenue and profit!○ Marginal Revenue and Marginal Profit are the difference when one additional unitof a good is produced● Costs as opportunity cost what you give up to get something● Firm's cost of production includes all the opportunity costs of producing goods○ Explicit Costs input costs that require an outlay of money by the firm (write acheck, supplies, loan payment, etc.)○ Implicit Costs Costs that do not require an outlay of money■ Implicit Costs are ignored by accountants■ Included by economists because they are interested in decision making● Things like, money that could have been earned through anotherjob or interest from money in bank)○ Total Costs Explicit Costs + Implicit Costs (for economists)● Economic profit is always < Accounting profit due to the inclusion of Implicit costs)○ Economic Profit  Total Revenue  Total cost (Explicit + Implicit)○ Accounting Profit  Total Revenue  total Explicit Costs● Production Function the relationship between quantity of inputs used to make a good○ The production function levels out quickly  at some point the additional workermakes very little difference in output (so Curve becomes flatter)○ Marginal product the increase in output from an additional unit of production■ represented by the slope of the production functionmarginal product of an input declines as the○ Diminishing Marginal product  quantity of the input increases (e.g. more workers)○ There is a strain on the factors of production  mainly labor■ eg. Overcrowding effect○ Total Cost Curve  the relationship between output and total costs■ Cost increases as output increases  at some point the cost curve gets verysteep.■ The result is Diminishing Marginal Product  same reason as for theproduction function Edited with the trial version of Foxit Advanced PDF EditorTo remove this notice, visit:www.foxitsoftware.com/shopping○ Fixed cost  costs that do not vary with quantity of output (eg. factory, rent etc) ■ You can recognize fixed cost easily because it does not change with quantity output ■ fixed costs are fixed (they are constant on a graph and they exist even when output is = 0) ○ Variable cost  Costs that change depending on quantity output. Often depends on the amount of workers ○ Total Costs (TC) = Fixed cost + Variable cost ● Average Fixed Cost (AFC) (Fixed Cost/quantity of output) ● Average Variable Cost (AVC) (Variable Cost/quantity of output) ○ Average Variable Costs increase with Quantity output ○ Average Fixed Costs decrease with Quantity output ● Marginal Cost increases as quantity increases ● MC and the ATC always cross at the ATC curves lowest point (ATC Curve is Ushaped!) ○ This is because anything lower than the average will bring the cost down and vice versa (think about the GPA example) ○ When MC<ATC  the average Total Cost is Falling ○ When MC>ATC  the average total cost is rising ● Remember: 3 Key things: ● (1) Marginal cost rises with the quantity of output. ● (2) The averagetotalcost curve is Ushaped. ● (3) The marginalcost curve crosses the averagetotalcost curve at the minimum of average total cost. Costs in the Short and Long Run: ● Fixed in the short run  Firms have less flexibility ● Variable in the long run  firms have more flexibility ○ ATC decreases as workers specialize and improve in the beginning (shortrun)  this levels off and then ATC increases in the long run due to distribution and management issues/costs ■ Short run  economies of scale (from Specialization) ■ Long run  diseconomies of scales (from increasing ■ coordination problems) ● As a result firms try to duplicate themselves ○ Build another firm Firms in competitive markets ● Competitive market is: ○ many buyers and sellers ○ Trading Identical products ○ Each buyer and seller are price takers  Firms have to accept price or go out of business ○ Firms can easily exit and enter the market ● Revenue of a competitive firm ○ Total Revenue = Price x Quantity ○ So Marginal Revenue = Price ● Average Revenue for a competitive firm  Total revenue divided by the quantity sold ○ Price = Marginal Revenue = Average Revenue Rules for maximizing profit: ● want to produce quantity where total revenue  total costs is biggest ● If MR>MC  should increase production ● IfMR<MC  should decrease production ● If MR = MC  profit is maximized!!! Price = Average Revenue = Marginal Revenue (good to remember this!) When Should a firm Shutdown (eg. Close a store at night) ● Shutdown ○ A shortrun decision to not offer services/produce goods ○ decision of when to shut down for a certain amount of time which depends on the market conditions during the time a firm decides to shut down ○ Firms decision depends on TR and VC ○ Shutdown if TR<VC for that period of time ○ Stay open if TR>VC for that period of time ○ In the Shortrun, a competitive firm’s supply curve (S) is the same as its Marginal Cost Curve (MC) ● Sunk Cost  a cost that has already been spent and cannot be recovered. ○ e.g. Bulk supplies, factory rent, factory technologies, etc. When Should A Firm Exit the Market ● In the long a firm needs to decide if it needs to exit the market  this decision is based on TR and TC (needs to include the fixed costs as well) ● A firm should exit if Revenue < than Total Costs ○ Exit if TR<TC (this is the same as P<ATC!!) ○ A firm should Enter if TR>TC or if P>ATC ○ Note: we include both fixed and variable costs in this decision Measuring Profit: ● if P>ATC = profit ○ Profit = TRTC=(PATC)xQ ● if P<ATC = loss ○ Loss=TCTR=(ATCp)xQ (negative profit) You can just do the area of the rectangle to get the profit! but know the above methods to calculate it without the presence of the graphs Since the Price is < the ATC  profit is negative  meaning there is a loss Profit maximization ● Long run  Exit