XVII.—On the Asymptotic Expansion of the Characteristic Numbers of the Mathieu Equation

1930 ◽  
Vol 49 ◽  
pp. 210-223 ◽  
Author(s):  
Sydney Goldstein

An asymptotic formula has recently been given for the characteristic numbers of the Mathieu equation From tabular values, it will be seen that the formula provides good numerical approximations to the characteristic numbers of integral order; but as pointed out by Ince, it provides better approximations to the characteristic numbers of order (m + ½), where m is a positive integer or zero. In this paper we shall first attempt to find out why this should be so, and then go on to show that the formula is probably an asymptotic expansion, in the Poincaré sense, for any characteristic number. A new asymptotic formula is then found for the difference between two characteristic numbers.

1968 ◽  
Vol 11 (2) ◽  
pp. 175-184 ◽  
Author(s):  
R.A. Smith

In following a suggestion of S. Chowla to apply a method of C. Hooley [3] to obtain an asymptotic formula for the sum ∑ r(n)r(n+a), where r(n) denotes the number of representations of n≤xn as the sum of two squares and is positive integer, we have had to obtain non-trivial estimates for the error term in the asymptotic expansion of1


1957 ◽  
Vol 3 (3) ◽  
pp. 132-134 ◽  
Author(s):  
M. Bell

The Mathieu functions of integral order [1] are the solutions with period π or 2π of the equationThe eigenvalues associated with the functions ceN and seN, where N is a positive integer, denoted by aN and bN respectively, reduce toaN = bN = N2when q is zero. The quantities aN and bN can be expanded in powers of q, but the explicit construction of high order coefficients is very tedious. In some applications the quantity of most interest is aN – bN, which may be called the “width of the unstable zone“. It is the object of this note to derive a general formula for the leading term in the expansion of this quantity, namelySuppose first that N is an odd integer. Then there is an expansionwhereThese functions π satisfyandOn Substituting (3) in (1), one obtains the algebraic equationwhereExplicitly,{11} = q{lm} = 0 otherwise.


1927 ◽  
Vol 46 ◽  
pp. 316-322 ◽  
Author(s):  
E. L. Ince

In a paper recently communicated to the London Mathematical Society the present author showed that the characteristic numbers an and bn of the Mathieu equation—may be developed, for large positive values of q, in the forms


1992 ◽  
Vol 35 (2) ◽  
pp. 189-199
Author(s):  
Bruce C. Berndt ◽  
Ronald J. Evans

An asymptotic expansion is given for the seriesas x→∞ in the sector |Argx|≦π/2–δ. Here δ, Re(a), and Re(s) are positive and r is a positive integer. In the case a = r = s = 1, this yields the nontrivial resultstated by Ramanujan in his notebooks [6].


1981 ◽  
Vol 24 (3) ◽  
pp. 179-195
Author(s):  
R. B. Paris

One of the many interesting problems discussed by Ramanujan is an approximation related to the exponential series for en, when n assumes large positive integer values. If the number θn is defined byRamanujan (9) showed that when n is large, θn possesses the asymptotic expansionThe first demonstrations that θn lies between ½ and and that θn decreases monotoni-cally to the value as n increases, were given by Szegö (12) and Watson (13). Analogous results were shown to exist for the function e−n, for positive integer values of n, by Copson (4). If φn is defined bythen πn lies between 1 and ½ and tends monotonically to the value ½ as n increases, with the asymptotic expansionA generalisation of these results was considered by Buckholtz (2) who defined, in a slightly different notation, for complex z and positive integer n, the function φn(z) by


1927 ◽  
Vol 46 ◽  
pp. 20-29 ◽  
Author(s):  
E. L. Ince

The characteristic numbers of the Mathieu equationare those values of a for which, when q is given, the equation admits of a solution of period π or 2π. The periodic solutions, or Mathieu functions, may be developed as a Fourier-series convergent for all values of q,multiplied by one or other of the factors


2012 ◽  
Vol 96 (537) ◽  
pp. 480-491 ◽  
Author(s):  
Stan Dolan

In a previous note [1], Fermat's method of descente infinie was used to prove that the equations.have no positive integer solutions. The geometrically based proof of [1] masked the underlying use of the difference of two squares. In the proofs of this article we shall make its use explicit, just as Fermat did [2, pp. 293-294].We shall use the elementary idea of the difference of two squares to develop a powerful technique for solving equations of the form ax4 + bx2y2 + cy4 = z2. This will then be applied to three problems of historical interest.


1960 ◽  
Vol 1 (4) ◽  
pp. 439-464 ◽  
Author(s):  
R. C. Thorne

AbstractUniform asymptotic formulae are obtained for solutions of the differential equation for large positive values of the parameter u. Here p is a positive integer, θ an arbitrary parameter and z a complex variable whose domain of variation may be unbounded. The function ƒ (u, θ, z) is a regular function of ζ having an asymptotic expansion of the form for large u.The results obtained include and extend those of earlier writers which are applicable to this equation.


Author(s):  
Öystein Rödseth

We denote by tm(n) the number of partitions of the positive integer n into non-decreasing parts which are positive or zero powers of a fixed integer m > 1 and we call tm(n) ‘the m-ary partition function’. Mahler(1) obtained an asymptotic formula for tm(n), the first term of which isMahler's result was later improved by de Bruijn (2).


2012 ◽  
Vol 86 (3) ◽  
pp. 389-404 ◽  
Author(s):  
GUOYOU QIAN ◽  
QIANRONG TAN ◽  
SHAOFANG HONG

AbstractLet k be any given positive integer. We define the arithmetic function gk for any positive integer n by We first show that gk is periodic. Subsequently, we provide a detailed local analysis of the periodic function gk, and determine its smallest period. We also obtain an asymptotic formula for log lcm0≤i≤k {(n+i)2+1}.


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