The Killers Happy Birthday Guadalupe!
A januári hatás, ritkán találni 77%os találati arányt a tőzsdén
http://kepfeltoltes.hu/view/100104/janeffect_www.kepfeltoltes.hu_.jpg
Nem gyenge történet :)
[This discussion is based on W. Biddle, "Skeleton Alleged in the Stealth
Bomber's Closet," _Science_ (May 12, 1989)]
Managerial economics is of great use in the aerospace industry, but this
does not mean that errors sometimes will not occur. The B-2 "Stealth" bomber
has cost billions to develop. According to Joseph Foa, an emeritus professor
of engineering at George Washington University, its design is fundamentally
flawed because two aerodynamicists made a mistake: they mistook a minimum
point for a maximum point.
The B-2 is basically a jet-powered "flying wing" aircraft. In a secret study
for the Air Force, the two aerodynamicists, William Sears and Irving Ashkenas
(then at the Northrop Corporation), used mathematical formulas to determine
how an aircraft's volume should be proportioned between wing and fuselage
in order to maximize its range. Taking the derivative of range with respect
to volume, they found that this derivative equaled zero when the total volume
was almost all in the wing. Hence, they concluded that a "flying wing" design
would maximize range.
But, in a subsequent analysis, Foa showed that the second derivative was
positive, not negative, under these circumstances. Thus, the "flying wing"
design minimized range; it didn't maximize it. In Foa's words, "The flying
wing was the aerodynamically worst possible choice of configuration."
This is a very interesting example of how important it is to look at the
second derivative to make sure that you do not confuse a maximation point
with a minimization point. While the backers of the B-2 bomber claim that
it is a good plane despite this error, no one denies that the error is an
embarrassment.
Megéltem már pár ilyet, hogy pont előttünk borult fel az autó :D !
Élőben látványosabb :D, csak az volt benne a rossz, hogy órákig állt a verseny :S !
Showder Klub - Beliczai Balázs [2/7] HQ
Showder Klub - Beliczai Balázs [1/7] HQ
Showder klub S04E01 Beliczai balázs
Blue - Get Down On It
