Digital Library of Mathematical Functions
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4 Elementary FunctionsComputation

§4.47 Approximations

Contents

§4.47(i) Chebyshev-Series Expansions

Clenshaw (1962) and Luke (1975, Chapter 3) give 20D coefficients for \mathop{\ln\/}\nolimits, \mathop{\exp\/}\nolimits, \mathop{\sin\/}\nolimits, \mathop{\cos\/}\nolimits, \mathop{\tan\/}\nolimits, \mathop{\cot\/}\nolimits, \mathop{\mathrm{arcsin}\/}\nolimits, \mathop{\mathrm{arctan}\/}\nolimits, \mathop{\mathrm{arcsinh}\/}\nolimits. Schonfelder (1980) gives 40D coefficients for \mathop{\sin\/}\nolimits, \mathop{\cos\/}\nolimits, \mathop{\tan\/}\nolimits.

§4.47(ii) Rational Functions

Hart et al. (1968) give \mathop{\ln\/}\nolimits, \mathop{\exp\/}\nolimits, \mathop{\sin\/}\nolimits, \mathop{\cos\/}\nolimits, \mathop{\tan\/}\nolimits, \mathop{\cot\/}\nolimits, \mathop{\mathrm{arcsin}\/}\nolimits, \mathop{\mathrm{arccos}\/}\nolimits, \mathop{\mathrm{arctan}\/}\nolimits, \mathop{\sinh\/}\nolimits, \mathop{\cosh\/}\nolimits, \mathop{\tanh\/}\nolimits, \mathop{\mathrm{arcsinh}\/}\nolimits, \mathop{\mathrm{arccosh}\/}\nolimits. Precision is variable.

§4.47(iii) Padé Approximations

Luke (1975, Chapter 3) supplies real and complex approximations for \mathop{\ln\/}\nolimits, \mathop{\exp\/}\nolimits, \mathop{\sin\/}\nolimits, \mathop{\cos\/}\nolimits, \mathop{\tan\/}\nolimits, \mathop{\mathrm{arctan}\/}\nolimits, \mathop{\mathrm{arcsinh}\/}\nolimits. Precision is variable.

§4.47(iv) Additional References

See Luke (1975, pp. 288–289) and Luke (1969b, pp.74–76).