# An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 9 Search : derivative
 antiderivative   کریای ِ نخستین   karyâ-ye naxostinFr.: primitive   The function F(x) is called the antiderivative of the function f(x) on the interval [a,b] if at all points of this interval F'(x) = f(x). Same as primitive.→ anti- + → derivative.Karyâ, → function; noxostin "primitive," → first. derivative   واخنه   vâxanéFr.: 1) dérivé; 2; 3) dérivée   1) General: Derived from another; not original or primitive. 2) Math.: For a → function  y = f(x), the → limit of the → ratio of the → increment of the function, Δy, to the increment of the → variable, Δx, as the latter tends to → zero. Derived function; result of → differentiation. 3) Chemistry: Substance derived or prepared from some other → substance.From M.E. derivatif, from L.L. derivativus, from derivat(us), p.p. of derivare, → derive + -ivus.Vâxané, noun from vâxan, present stem of vâxanidan, → derive. first derivative   واخنه‌ی ِ نخست   vâxane-ye naxostFr.: dérivée première   The simplest mathematical → differentiation of one quantity relative to another; df(x)/dx. It is the same as → derivative, contrasted with the → second derivative or the nth derivative.→ first; → derivative. first derivative test   آزمون ِ واخنه‌ی ِ نخست   âzmun-e vâxane-ye naxostFr.: teste de la dérivée première   In → calculus, a method for determining whether an → inflection point is a → local minimum, → local maximum, or neither.→ first; → derivative; → test. first-order partial derivative   واخنه‌ی ِ پاری ِ رایه‌ی ِ نخست   vâxane-ye pâri-ye râye-ye naxostFr.: dérivée partielle du premier degré   For a → function with several → variables, the derivative, done only once, with respect to one of the variables. For example ∂u/∂x for u = u(x,y).→ first; → order; → partial; → derivative. partial derivative   واخنه‌ی ِ پاری   vâxane-ye pâriFr.: dérivée partielle   The derivative of a function of two or more variables, e.g., z = f(x,y), with respect to one of the variables, the others being considered constants (denoted ∂z / ∂x).→ partial; → derivative. period derivative   واخنه‌ی ِ دوره   vâxane-ye dowréFr.: dérivée de la période   The rate at which the rotation period of a → pulsar changes over time. This quantity, dP/dT, can range from as small as 0.05 picoseconds per year (1.5 x 10-21 seconds per second) to as large as about 10 milliseconds per year (4.2 x 10-10 seconds per second). For the → Crab pulsar, the period derivative is 4.2 x 10-13 s s-1, implying a decrease in the star's → rotation energy of about 4.5 x 1038 erg s-1. Period derivative is a very important parameter for the determination of the pulsar age.→ period; → derivative. second derivative   واخنه‌ی ِ دوم   vâxane-ye dovomFr.: dérivée seconde   In → calculus, the → derivative of a → first derivative. It is usually written as f''(x), d2y/d2x, or y''.→ second; → derivative. second derivative test   آزمون ِ واخنه‌ی ِ دوم   âzmun-e vâxane-ye dovomFr.: test de la dérivée seconde   A method, used in → calculus, for determining whether a given → stationary point of a → function is a → local minimum or → local maximum.→ second; → derivative; → test.