Mark Zuckerberg on Taking Risks and Finding Talented People

So I have written here the formal definition for the partial derivative of a two-variable function with respect to X. What I want to do is build up to the formal definition of the directional derivative of that same function in the direction of some vecto…

Humans to Mars does not require building some gigantic nuclear powered interplanetary spaceship. We can do it with the kinds of technology we either have today or know how to build today. We need to have a heavy lift booster. We take two such boosters fo…

My name is Marcia and I’m 11 years old. My name is Mary and I’m 11 years old. When they see us together, some don’t believe that we’re twins. They don’t believe us; they’re like, “Oh really? I never noticed that. I thought you were just friends,” because …

How have President Reagan’s policies affected the government since he left office? What Ronald Reagan did was set up a titanic debate, really, between those who believed in the New Deal view of government—which was that it was there to help those who cou…

Hello and welcome to Ed Talks with Khan Academy! Thank you for joining us today. I’m Kristen Decervo, the Chief Learning Officer at Khan Academy, and I’m excited today to talk with Nick Ferroni, who’s going to talk about what it would look like if we real…

Imagine this: I’m in Tanzania and I am about to enter the airport in Dar es Salaam. I have a large suitcase with elephant tusks inside. I’m trying to put all the bags in together to try to mask, and the bags go through. Then he says the worst thing an air…