Safari Live - Day 42 | National Geographic

A 20 meter ladder is leaning against a wall. The distance ( x(t) ) between the bottom of the ladder and the wall is increasing at a rate of 3 meters per minute. At a certain instant ( t_0 ), the top of the ladder is a distance ( y(t_0) ) of 15 meters from…

We started our two-day journey through the jungle toward the world’s largest cave. We’re here to photograph this cave in 360-degree images. You know we have to descend into vast empty darkness. I have a cold sensation along my spine, feeling like, how on …

We’re told Cassandra was curious if triangle ABC and triangle GFE were congruent, so he tried to map one figure onto the other using a rotation. So, let’s see. This is triangle ABC, and it looks like at first he rotates triangle ABC about point C to get i…

How exactly did the founders of the United States first decide on how to choose the first president? Hi, I’m Leah from KH Academy. We’re celebrating this President’s Day by taking a look at how the US presidency is shaped in the US Constitution. There a…

We are now going to study the magical Republic of Fitlandia. As we often do in economics, we’re going to assume that Fitlandia, which of course does not exist in the real world, is a very simple country. It helps us create a model for it. Let’s say that F…

I’m very very excited to introduce our next speaker. Paul Buchheit is one of my partners at Y Combinator. He also was one of the very early employees at Google, where he’s known as the inventor of Gmail and the creator of the “don’t be evil” motto. He als…