http://www.youtube.com/watch?v=w-I6XTVZXww Unbelievable: 1+2+3+4.... = -1/12 ? The above video by the excellent team at Numberphile has caused a bit of an internet stir - by providing a proof that 1+2+3+4+5+... = -1/12 It's well worth watching as an example of what proof means - if something is proved which we "know" is wrong, then should... Continue Reading →