Hey! How ya doin' econ students? This Mr. Clifford. Welcome to ACDC econ.
Right now we're going to talk about perfect competition. Because I know a few things
Because I know a few things about being perfect.
[Mumbles] stupid
Alright before jumping to perfect
competition let's take a step back and
talk about the four market structures. Every product out there is produced in a market
that's one of these for market structures
there's perfect competition, monopolistic competition,
oligopoly and monopoly.
I'm going to explain perfect competition this video
but the other market structure: imperfect competition
is also super important.
A great example of a product that is produced in perfect competition is
oranges or strawberries or milk.
No, NO, Paul, I'm not drinking another gallon of milk!
You'll remember that firms inside perfect
competition have several characteristics
the most important one is that their
products are completely identical
as other firms, that means that they're
perfect substitutes for each other.
Think about,
a dairy farmer can't taste milk and
determine if that was his cow or some other
cow that produced that milk.
It's the same way with all other firms are in
perfect competition
another key characteristic is that
there's many small firms and plenty of
people producing this product.
Now, if you put those together, you find out that these firms
are: price takers.
This means they have
to take price that is set by the market.
So, they have no control over the price.
It'll make more sense if I show it to you in graphs.
What we have right here is the market for milk.
You learned this before, it's got demand and supply and it sets an
equilibrium at ten dollars.
so this is the industry graph, or the
market graph, that includes all the different
firms that produce milk.
Right here is the graph for one individual firm
Since their price takers, the demand for
this firm is horizontal it is perfectly elastic.
This is because they have no control over the
price
If they raise the price up, to 11, then
no one is going to go to them, they will go to all the
other dairy farmers
and there's no reason for them to lower
the price below 10, because people
are going to buy as many units they sell, at ten dollars
this horizontal demand curve is the demand, but is also equal to marginal revenue
The marginal revenue is the additional
revenue the firm gets when they sell another unit.
So, if they sell another crate for ten
dollars, their additional revenue is ten dollars
They sell another crate, for another ten
dollars, additional revenue is ten dollars.
So, the demand equals the marginal revenue. It also equals the average revenue and the price.
And your teacher will tell you that this is sometimes called Mr. DARP. (MR=D=AR=P)
(Ehhhhhh)
That's something I do my classes
anytime I say the word MR=D=AR=P
the students have to go: Ehhhhhhh
This is the horizontal demand curve which equals the marginal revenue curve.
Mr. DARP. (ehhhhhh)
The point is, the demand and the marginal revenue are horizontal for the firm.
Now, if we take some cost curves and put it on here,
we can actually figure out how many units this firm should produce
and we can calculate profits.
Let's zoom in on the fim. Notice, we have a marginal cost curve and an ATC.
The first question is to figure out how many units they should produce.
That brings up the most important
concept in all of microeconomics:
Which is the profit maximizing rule. 
All firms should produce where
MR equals MC.
This is basically saying that you should always produce as long as the marginal revenue
is greater than the marginal cost.
At the point where the equal you should stop
producing and that is the profit maximizing quantity.
if you produce for the marginal cost is
greater than marginal revenue, you make
less profit than before.
This firm is going to produce where MR hits MC, which is right there, at 10 units.
they don't wanna stop at four units
because they can still produce more profit
And they don't want to produce eleven units because
the additional cost is greater than the additional revenue of selling that unit.
This is why you spent so much time learning about all the cost curves.
You put them together with the rescue  curves and now you can figure out how many
units should a firm produce
what is their total revenue, their total cost
and how much is profit
In this case, they're selling 10 units
for ten dollars each. That big box, right there, is total revenue.
Now, is that all profit?
No, because some of it is cost. To calculate the total cost, you have to find
the average total cost of each unit. Which is six dollars.
6 x 10 = 60 
That box, in yellow, is the total cost.
Total revenue of 100, minus 60 total cost
gives you 40 dollars profit, green box
This individual firm is maximizing
profit we're at MR = MC
and they're making economic profit of $40 or four dollars per unit.
This graph is a firm in a perfectly competitive industry.
and that's graph that you will have to draw
and analyze do well on your tests.
Make sure you feel comfortable drawing
these side by side graphs; the market and
the firm.
with the firm showing profit or showing
a loss
or breaking-even in the long-run
equilibrium. Another thing you should be able to
do other than just draw the graph is
use a chart to calculate how much profit is being made.
You will learn how to do that in the next video.
Hey, I hope this video helped you to understand perfect competition.
If you like these videos, make sure to subscribe. 
Check out the next video that will
explain the whole thing over again except using charts. Also, take a look at
my microeconomics review video that covers
all the concept of microeconomics. 
It'll get you ready for your final
or for your AP tests. Alright, 'till next time.
