00:01
So first of all, i'm pretty sure this equation transpos just a little bit when someone wrote it down, right? it makes no sense for there to be two constants here, right? as written, it's 97 .7 minus 2 .5 px plus 3 .1 p .y minus 2 .1.
00:18
That qx is the quantity demanded.
00:20
That's the explanatory text, but that equation has no y in it.
00:24
So i'm going to say that 2 .1 is multiplied by y because there's no reason we'd have two constants in this.
00:30
Equation, right? so check this assumption, but i'm pretty sure this is, right? it just looks like there was a slight error in transcribing this equation.
00:41
So, especially, you know, they told us what y is.
00:43
It has to be in this equation somewhere.
00:46
And it doesn't make sense for there be two constants.
00:48
So now we need to find the elasticity of demand, right? the own price elasticity is usually expressed as the the percentage change in the quantity of x with respect to the percentage change in the price of x, right? that's the normal formula.
01:09
But you can rewrite this in terms of calculus, if you so desire.
01:15
This is dqx, d -px times px over qx.
01:22
This is equivalently the formula for the own price elasticity, right? which hopefully you've seen before...