Re: help (with Bessel)

On Fri, 2003-11-14 at 02:01, frerejacque wrote:
chengj a écrit :

Hi !
Now I found a big problem : bessely(4.5,6) = -0.9846543023 in OPEN
in excel
But when I compute Bessely using MATLAB ,the result was
( -0.05459791739132197 in Mathematica)

some one who can tell me which one is right ?????

Thank you very much !!!
there is a book issued in 1966 by the
National Bureau of Standards for $6.50 in 1966
and tabulating a lot of special functions
with some mathematics too:

Assuming the question is the value of
the Bessel function:
Y, of fractional order 4.5 for x=6.

Ah, but that is not what bessely(4.5,6) in XL, gnumeric, and OO stands
bessely(4.5,6) is the value of the Bessel function Y of order 6 for


Looking at page 437:

Y(4.5, x) = sqrt((2x)/pi)* y(4, x)
y beeing the spherical bessel function
of the second kind.

y(4,x) is tabulated to 5 places in table 10.2 
page 462 and
y(4, 6)= -2.7936E-2.
back to the hand computing device
Y(4.5, 6) = sqrt(12/pi)*-2.7936E-2
= - 0.054598
with five decimal places:

CONCLUSION: The value given in
Mathematica and Mathlab agrees with
ye old math tables.

Why OPPENOFFICE and EXCEL do'nt is an 
other problem

Daniel Frerejacque
Paris (France)

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Andreas J. Guelzow
Taliesin Software, Shelties, Pyrsheps
and Shetland Sheep

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