History of The Weather Channel originally generated only text-based products. Radar imagery was added to the units in June of that year, with graphical backgrounds being introduced in July, making the 4000 the first STAR to be capable of generating graphics and the first to incorporate the channel's logo in the forecast segments. Also in 1990, The Weather Channel began including snow condition reports at five minutes after the hour. Largely considered the height of the classic TWC by enthusiasts, The Weather Channel underwent a major graphical revamp (with the introduction of a new slogan, "Weather You Can Always Turn To") on March 6, 1991.
Proof that e is irrational fraction, "e" is irrational. A short proof of the previous equality is known. Since the simple continued fraction of "e" is not periodic, this also proves that "e" is not a root of second degree polynomial with rational coefficients; in particular, "e" is irrational. The most well-known proof is Joseph Fourier's proof by contradiction, which is based upon the equality Initially "e" is assumed to be a rational number of the form ⁄. Note that "b" could not be equal to 1 as "e" is not an integer. It can be shown using the above equality that "e" is strictly