释义 |
TangentThe tangent function is defined by
 | (1) |
where is the Sine function and is the Cosine function. The word ``tangent,'' however, alsohas an important related meaning as a Line or Plane which touches a given curve or solid at a single point. These geometrical objects are then called a Tangent Line or Tangent Plane, respectively.
The Maclaurin Series for the tangent function is
where is a Bernoulli Number.
is Irrational for any Rational , which can be proved by writing as a Continued Fraction
 | (3) |
Lambert derived another Continued Fraction expression for the tangent,
An interesting identity involving the Product of tangents is
 | (5) |
where is the Floor Function. Another tangent identity is
 | (6) |
(Beeler et al. 1972, Item 16).See also Alternating Permutation, Cosine, Cotangent, Inverse Tangent, Morrie's Law,Sine, Tangent Line, Tangent Plane References
Abramowitz, M. and Stegun, C. A. (Eds.). ``Circular Functions.'' §4.3 in Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, 9th printing. New York: Dover, pp. 71-79, 1972.Beeler, M.; Gosper, R. W.; and Schroeppel, R. HAKMEM. Cambridge, MA: MIT Artificial Intelligence Laboratory, Memo AIM-239, Feb. 1972. Spanier, J. and Oldham, K. B. ``The Tangent and Cotangent Functions.'' Ch. 34 in An Atlas of Functions. Washington, DC: Hemisphere, pp. 319-330, 1987.
|