I hope the exam went well.

@DrAzevedoEcon well, not really I got 60 (Average in class is 30)

This is a good question, and you are correct that it is a little less obvious than the demand case. The problem with what you're thinking is that you are changing something in the background. In other words, you're violating the ceteris paribus assumption. You're saying that if you want to earn the same income, and the price falls, you would want to sell more to make up for the fact that the price is lower. There's nothing wrong with that logic, but if you want to understand why the supply curve is upward-sloping, you have to only change the price while holding everything else constant. In other words, don't impose the constraint that you need to generate the same revenue. Here's a way of thinking about it that may help isolate just the impact of the price change. Suppose a young person had the opportunity to do some manual labor for three dollars an hour. It's likely that they wouldn't sell any of their labor for that price. Now suppose that the wage was $15 per hour. That would likely induce them to sell some labor. If the wage was $100 per hour, they would probably want to sell even more labor. If you want more information on why the supply curve is upward-sloping, watch my videos on perfect competition. Let me also add that there can be times when a labor supply curve can have a downward-sloping portion to it. We call it a backwards-bending labor supply curve.

I'm glad to hear the videos are helpful for you.

just calculate the derivate and the numbers dont match

Is the mid point method more accurate?

I'm not completely sure I understand your question, but I'll give it a shot. When we calculated the elasticity of demand for pizzas using the midpoint method, we got -1.5. I then said something about a previous calculation where we got an answer of -2. Treat those as two completely different problems. We didn't have to calculate the percent changes in the first problem because we started with them. I hope that answers your question.

yeah he did gave a link .... i have them downloaded

Correct...from an overall perspective, a tariff would reduce world welfare.

If you'll go back and take another listen to the 28-minute mark, you'll see that I am indeed talking about the sellers being represented by the supply curve. If we're talking about the right side of the picture, the non-sellers are on the top side and the non-buyers are on the lower side.

At this point, the only macro videos that I have are for principles of macroeconomics. kzbin.info/www/bejne/hGjGgpyod9miaM0si=LD6Hx1-RsixgmTRl

The best way to watch would be by going to a playlist. I have playlists for Principles of macroeconomics, principles of microeconomics, and international economics. The videos are in order for each playlist.

Thanks for watching!

Thanks for watching! I'm glad to hear the videos are useful.

Thanks for watching!

Thanks for watching!

Principles of microeconomics by N.Gregory Mankiw 5th edition And it's chapter 13 (page 267 of book and page 292 of pdf)

Correct...I use Mankiw's textbook.

Great! I'm glad it was helpful.

Thanks for watching!

You're welcome!

Thanks for watching!

Keep in mind that whether a good is an inferior or normal good is a characteristic of your preferences, and what is an inferior good for one person may not be an inferior good for another person. With public transportation, in locations with high population density, public transit probably isn't an inferior good for many people. However, in many towns and cities that don't have extensive, reliable public transit systems, it's probably an inferior good for most people. In those locations, as people's income rises, they tend to buy a vehicle.

Thanks for watching! I'm glad the videos have been useful.