background preloader

Math

Facebook Twitter

Here's How Fictional Dust Explains Radio Static. Youtube. Two envelopes problem. The two envelopes problem, also known as the exchange paradox, is a brain teaser, puzzle, or paradox in logic, philosophy, probability, and recreational mathematics. It is of special interest in decision theory, and for the Bayesian interpretation of probability theory. Historically, it arose as a variant of the necktie paradox. The problem: You have two indistinguishable envelopes that each contain money. One contains twice as much as the other. It can be argued that it is to your advantage to swap envelopes by showing that your expected return on swapping exceeds the sum in your envelope. Example Assume the amount in my selected envelope is $20. However if I happened to have selected the smaller of the two envelopes, that would mean that the amount in the other envelope is twice the amount in my envelope.

A large number of solutions have been proposed. Problem[edit] Basic setup: You are given two indistinguishable envelopes, each of which contains a positive sum of money. Futurama Writer Invented A New Math Theorem Just To Use In The Show. What's the rarest figure eight in the universe? The N Body problem problem has always been an issue in celestial mechanics. For example our solar system, over very large time scales is actually unstable. This is because it's not really a two body system, unless we enormously simplify the solar system just down to the Earth and Sun, ignoring the Moon, the asteroids, Mars, Saturn and all the rest of it. The affects of the gravitational perturbations of all these other bodies, although very small on short time scales, can add up to be instability in the long run. The solar system is in fact a chaotic pendulum: Factor in the motions of other stars in the galaxy and energy lost due to gravitational radiation and over many quadrillions of years the solar system will fall apart.

That vaguely related tidbit aside. Simple animation to explain complex principles. 1, aircraft radial engine 2, oval Regulation 3, sewing machines 4, Malta Cross movement - second hand movement used to control the clock 5, auto change file mechanism 6, auto constant velocity universal joint 6.gif 7, gun ammunition loading system 8 rotary engine - an internal combustion engine, the heat rather than the piston movement into rotary movement # Via World Of Technology. 1, inline engine - it's cylinders lined up side by side 2, V-type engine - cylinder arranged at an angle of two plane 3, boxer engine - cylinder engine arranged in two planes relative.

Googol and Googolplex - Numberphile. Do numbers EXIST? - Numberphile. Tau Day | No, really, pi is wrong: The Tau Manifesto by Michael Hartl. I continue to be impressed with how rich this subject is, and my understanding of π and τ continues to evolve. On Half Tau Day, 2012, I believed I identified exactly what is wrong with π. My argument hinged on an analysis of the surface area and volume of an n-dimensional sphere, which (as shown below) makes clear that π doesn’t have any fundamental geometric significance. My analysis was incomplete, though—a fact brought to my attention in a remarkable message from Tau Manifesto reader Jeff Cornell.

As a result, this section is an attempt not only to definitively debunk π, but also to articulate the truth about τ, a truth that is deeper and subtler than I had imagined. Note: This section is more advanced than the rest of the manifesto and can be skipped without loss of continuity. 5.1 Surface area and volume of a hypersphere We start our investigations with the generalization of a circle to arbitrary dimensions.

Which consists of the two points ±r. Is the line segment from −r to r. N!!