Demand for normal goods increases when income increases, but demand for inferior goods decreases when income increases. In this video, we use the example of a computer and a car to describe the concepts of normal goods and inferior goods and show how a change in income affects the demand for each using a graph of the demand curve. Created by Sal Khan.

Positive statements are fact-based, but normative statements are based on opinions. In this video, learn about the distinction between positive statements and normative statements, and why economists emphasize positive analysis vs. normative analysis, as well as how to identify positive statements vs. normative statements.

Object Image and Focal Distance Relationship (Proof of Formula). Created by Sal Khan.

Competition runs across a spectrum from perfectly competitive to monopoly, and two types of competition that lie within this spectrum are monopolistic competition and oligopolies. In this video, we briefly compare these two forms of competition. Created by Sal Khan.

When does an oligopoly act more like a perfectly competitive firm, and when does it act more like a monopolist? Find out in this video. Created by Sal Khan.

Understanding the mechanics of an open end mutual fund a bit better. Created by Sal Khan.

Basic difference between traditional open market operations and quantitative easing. Created by Sal Khan.

Looking at how regulatory DNA sequences can repress or promote gene transcription (particularly in bacteria operons).

The British wage two wars on China to have better access to Chinese markets, especially to sell opium grown in British India.

Opportunity cost is the value of something given up to obtain something else. In this video, we explore the definition of opportunity cost, how to calculate opportunity cost, and how the PPC illustrates opportunity cost. Created by Sal Khan.

In this video, we use the PPCs for two different countries that each produce two goods in order to create an output table based on the data in the graph. We then use the output table to determine the opportunity costs of producing each good. Finally, we determine which country has a comparative advantage in each good.

In this video, we use the PPCs for two different countries that each produce two goods in order to create an output table based on the data in the graph. We then use the output table to determine the opportunity costs of producing each good. Finally, we determine which country has a comparative advantage in each good.

A rational agent considers all costs, including explicit and implicit costs, when deciding whether or not to undertake an action. In this video, learn about how opportunity costs represent the cost of the next best alternative.

You want a projectile to fly as far as possible, at which angle should you launch it? We'll start with formulas for the initial velocity. Created by Sal Khan.

Using indifference curves to think about the point on the budget line that maximizes total utility. Created by Sal Khan.

Using some basic calculus to show that marginal revenue has twice the slope of the demand curve for a monopolist. Created by Sal Khan.

In this video we explore how aspects of an option's expiration affect the option's price. Created by Sal Khan.