cylonlover writes: NASA launched a strategic partnership with location-based social networking site foursquare in 2010 with the first-ever check-in from the International Space Station (ISS) by astronaut Doug Wheelock. Now the space agency has gone one better with the first check-in on another planet thanks to its Curiosity Mars rover. Since fellow foursquare users will have a hard time checking in on the Red Planet themselves, they’ll instead be able to earn a Curiosity-themed badge for visiting locations relating to science, technology, engineering and mathematics. The badge will be available later this year and is designed to spark the scientific curiosity of foursquare users by encouraging them to visit science centers, laboratories and museums.
We warn the reader in advance that the proof presented here depends on a
clever but highly unmotivated trick.
-- Howard Anton, "Elementary Linear Algebra"