Microeconomics CLEP - Price Elasticity

[BeeMarie]

I've just started working on Microeconomics study and I haven't went through the flash cards yet. I'm trying to 'get' the algebra concept of elasticity.

If I'm given the actual percentages in a question, I think should be able to figure the elasticity as (% change in rise)/(% change in run).

But, if I'm given prices or quantities etc. and asked to calculate the % change and the elasticity, then could I use the difference quotient? I've read that the average (or midpoint) is what they actually use.

difference quotient: f(x) = f(x+h) - f(x) / h

If it isn't that, then I think it is the midpoint formula. ???


Does anyone know the answer to this question? Or if I probably won't be asked to figure that, then let me know so I don't waste time trying to figure it out

Thanks,
Bee