…
►Because the
series (
3.11.12) converges rapidly we obtain a very good first approximation to the minimax polynomial
for
if we
truncate (
3.11.12) at its
th term.
…
►Since
,
is a monotonically increasing function of
, and (for example)
, this means that in practice the gain in replacing a
truncated Chebyshev-
series expansion by the corresponding minimax polynomial approximation is hardly worthwhile.
…
►Let
be the last term retained in the
truncated series.
…Then the sum of the
truncated expansion equals
.
…
►be a formal power
series.
…
…
►As of September
20, 2021, Nemes performed a complete analysis and acted as main consultant for the update of the source citation and proof metadata for every formula in Chapter
25 Zeta and Related Functions.
…
…
►As of September
20, 2022, Groenevelt performed a complete analysis and acted as main consultant for the update of the source citation and proof metadata for every formula in Chapter
18 Orthogonal Polynomials.
…
…
►First, we introduce the
truncated functions
and
defined by
►
2.5.21
►
2.5.22
…
►Since
, by the Parseval formula (
2.5.5), there are real numbers
and
such that
,
, and
…
►To verify (
2.5.48) we may use
…
…
►
§20.11(ii) Ramanujan’s Theta Function and -Series
…
►With the substitutions
,
, with
, we have
…
►In the case
identities for theta functions become identities in the complex variable
, with
, that involve rational functions, power
series, and continued fractions; see
Adiga et al. (1985),
McKean and Moll (1999, pp. 156–158), and
Andrews et al. (1988, §10.7).
…
►As in §
20.11(ii), the modulus
of elliptic integrals (§
19.2(ii)), Jacobian elliptic functions (§
22.2), and Weierstrass elliptic functions (§
23.6(ii)) can be expanded in
-
series via (
20.9.1).
…
►For applications to rapidly convergent expansions for
see
Chudnovsky and Chudnovsky (1988), and for applications in the construction of
elliptic-hypergeometric series see
Rosengren (2004).
…