If the Kâ¬ level is changed from 1 to 2. called the Taguchi method or Taguchi quality engineering in the United States and other countries. the coefï¬cient is expected to decrease to zero. we cannot lower the quadratic termâs coefï¬cient.
Today, that single bitcoin is worth upwards of  $2,200. Monday marked the seventh anniversary of what is said to be the first recorded instance of bitcoin used in a real world transaction. Over the course of seven years, bitcoin's value has multiplied 879,999 times over since 2010.
Bitcoin, the decentralized electronic currency that may or may not be a libertarian fantasy, has had a rollercoaster of a week. Its value peaked at a staggering $266 on Thursday before plummeting to $71 Friday, according to Mt. Gox, one of cyberspace's leading Bitcoin exchanges. (Watch a three-minute Bitcoin explainer here.) At the beginning of this year, a single Bitcoin was worth just $13. And when the virtual currency launched in 2009, each coin traded for mere pennies. That means a lot of early buyers have gotten very, very rich.