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.
Irrational number rely on deductive reasoning for proof.” This method of exhaustion is the first step in the creation of calculus. Theodorus of Cyrene proved the irrationality of the surds of whole numbers up to 17, but stopped there probably because the algebra he used could not be applied to the square root of 17. It was not until Eudoxus developed a theory of proportion that took into account irrational as well as rational ratios that a strong mathematical foundation of irrational numbers was created. Geometrical and mathematical problems involving irrational numbers such as square roots were addressed very early during the