Constant unit elasticity발음듣기
Constant unit elasticity
We've already talked about linear demand functions that actually have changing price elasticity as we go down the curve.발음듣기
What I want to do in this video - and it'll be a quick little video - is think about can we construct a demand curve, or at least understand what it looks like, that has a constant elasticity across the curve?발음듣기
And hopefully, it will give us a bit more intuition on how this elasticity business even works.발음듣기
Now let's put some numbers there that'll just help us draw this demand curve that has unit elasticity at every point, at every price, in every quantity.발음듣기
And then this is 10 units per time period, 10 units per week, or 10 units per month, or whatever else.발음듣기
And we're going to assume that this curve meets the law of demand, which means as price goes down, quantity demanded goes up.발음듣기
This is going to be a downward sloping, so really we're going to say that the elasticity of demand is going to be equal to negative 1.발음듣기
If we have a 1% decrease in price, we're going to have a 1% increase in quantity, and vice versa.발음듣기
If we're up here, where the price is near $10, and maybe where the quantity is closer to $1, let's think about what a 10% movement in price would look like, a 10% movement down.발음듣기
Once again, we want 10% for both of them, because we want the price elasticity of demand to be 1 throughout the curve.발음듣기
So if we go over here, a 10% movement in price - so let's say we're down here, where price is close to 1 - a 10% movement in price is going to be very small.발음듣기
It's going to look something like that, because the quantity is approaching 10, so 10% of that is about 1 unit just like that.발음듣기
And then when the price and the quantity is about the same, so let's say this point right over here, where the price and the quantity is about the same - so let's say that that is 2, this is 3, this is 2, this is 3 right over here - your percent movements are going to be the same.발음듣기
But since the price and quantity are the same, the absolute movements are also going to be the same.발음듣기
And so if you connect the dots, you get the general shape of a demand curve that has a price elasticity of demand at negative 1 throughout the curve, or whose absolute value of the price elasticity of demand is 1.발음듣기
So the curve would look something like - I'll just draw a dotted line; it's easier to do - so it'll look something like that.발음듣기
It'll keep getting steeper as we get the quantity closer to 0, and it'll keep flattening out as the quantity grows and grows and grows.발음듣기