Friday, December 24, 2010

Miss TSA

You've probably heard the U.S. Federal Government wastes money, but did you ever consider exactly HOW?


Sorry, not my type. She's just skin and bones.

Friday, December 17, 2010

Dream Cars: 2011 Genesis Coupe 3.8 Track

With 2 kids in college and "broke" being a step up for me (in debt with used car payments, so I'm less than zero), I have no money let alone $32,000 to buy this car. Nor do I have a logical reason to own one, as vans and station wagons are much more practical.

Still, I've seen this new brand on the road lately, and it looks sweet. So I would if I could but I can't so I won't. Midlife crisis, much?


I look at it this way: If any person deserved to own a Stradivarius violin, it was Albert Einstein. But he probably didn't. He made due with what he had, and did OK I've heard.

Wednesday, November 17, 2010

Feigenbaum Constant Approximations

Feigenbaum Constant Approximations
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A curious approximation to the Feigenbaum constant delta is given by

 pi+tan^(-1)(e^pi)=4.669201932...,
(1)

where e^pi is Gelfond's constant, which is good to 6 digits to the right of the decimal point.

M. Trott (pers. comm., May 6, 2008) noted

 delta approx 2G+3,
(2)

where G is Gauss's constant, which is good to 4 decimal digits, and

 delta approx 9/T,
(3)

where T is the tetranacci constant, which is good to 3 decimal digits.

A strange approximation good to five digits is given by the solution to

 x^x=1333,
(4)

which is

 x=e^(W(ln1333))=4.669202878...,
(5)

where W(z) is the Lambert W-function (G. Deppe, pers. comm., Feb. 27, 2003).

 delta approx (10)/(pi-1)
(6)

gives delta to 3 digits (S. Plouffe, pers. comm., Apr. 10, 2006).

M. Hudson (pers. comm., Nov. 20, 2004) gave

delta approx (1182102)/(773825)+pi
(7)
 approx (46875)/(15934)-sqrt(2)+pi
(8)
 approx tan((1954)/(1781))+e,
(9)

which are good to 17, 13, and 9 digits respectively.

Stoschek gave the strange approximation

 delta approx 4(1+(12^2)/(163)+(4·12^2+31)/(4·163^2)+...)/(1+(10^2)/(163)+(10^2+30)/(163^2)+...),
(10)

which is good to 9 digits.

R. Phillips (pers. comm., Sept. 14, 2004-Jan. 25, 2005) gave the approximations

delta approx 3/2pi-e^(-pi)
(11)
 approx pi+e-tan^(-1)|alpha|
(12)
 approx (e^(10)-e^9)/(e^8+1)
(13)
 approx 3/2pi-(e^(-pi))/(1+exp(-8+e^(-1/2)))
(14)
 approx pi-tan^(-1)[(e-1)^(-16)-e^pi],
(15)
 approx (e(e-1))/(1+exp{8[(1+e^(-8))^(3/2)-2]})
(16)

where e is the base of the natural logarithm and e^pi is Gelfond's constant, which are good to 3, 3, 5, 7, 9, and 10 decimal digits, respectively, and

|alpha| approx (e/(e-1))^2
(17)
 approx tan(e-delta)
(18)
 approx tan[e-tan^(-1)(e^pi)]
(19)
 approx -cot(e+e^(-pi))
(20)
 approx tan[e+tan^(-1)(2/((e-1)^8e)-e^pi)]
(21)
 approx (e^2)/((e-1)^2-e^(-(3+sqrt(26))))
(22)
 approx (e^2)/((e-1)^2-exp(-8-e^(-1/lnlndelta)),)
(23)

which are good to 3, 3, 3, 4, 6, 8, and 8 decimal digits, respectively.

An approximation to mu_infty due to R. Phillips (pers. comm., Jan. 27, 2005) is obtained by numerically solving

 x=e^(sqrt(phi))(1+2/(e^8lnx)),
(24)

for x, where phi is the golden ratio, which is good to 4 digits.

SEE ALSO: Almost Integer, Feigenbaum Constant