arithmetic mean miyângin hesâbi (#) Fr.: moyenne arithmétique Of n numbers a_{1}, a_{2}, ..., a_{n}, the quantity defined as: (a_{1} + a_{2} + ... + a_{n})/n. → arithmetic; → mean. |
geometric mean miyângin-e hendesi (#) Fr.: moyenne géométrique The middle term in a → geometric progression. Of two terms, the geometric mean is the square root of their product. For example, the geometric mean of 4 and 9 is ± 6. For a series of n terms, it is expressed as: (a_{1}.a_{2}. ... .a_{n})^{1/n}. |
Greenwich Mean Sidereal Time (GMST) zamân-e axtari-ye miyângin-e Greenwich Fr.: temps sidéral moyen de Greenwich The → sidereal time related to the angle between the → prime meridian and the → mean vernal equinox, measured in the plane of the equator. → mean; → Greenwich Meridian; → sidereal; → time. |
harmonic mean miyângin-e hamâhang Fr.: moyenne harmonique A number whose reciprocal is the → arithmetic mean of the reciprocals of a set of numbers. Denoted by H, it may be written in the discrete case for n quantities x_{1}, ..., x_{n}, as: 1/H = (1/n) Σ(1/x_{i}), summing from i = 1 to n. For example, the harmonic mean between 3 and 4 is 24/7 (reciprocal of 3: 1/3, reciprocal of 4: 1/4, arithmetic mean between them 7/24). The harmonic mean applies more accurately to certain situations involving rates. For example, if a car travels a certain distance at a speed speed 60 km/h and then the same distance again at a speed 40 km/h, then its average speed is the harmonic mean of 48 km/h, and its total travel time is the same as if it had traveled the whole distance at that average speed. However, if the car travels for a certain amount of time at a speed v and then the same amount of time at a speed u, then its average speed is the arithmetic mean of v and u, which in the above example is 50 km/h. |
mean 1) miyângin (#); 2) cemârdan Fr.: 1) moyenne; 2) signifier, vouloir dire 1a) General: A quantity having a value intermediate between the values of other
quantities; an average. 1) From O.Fr. meien, from L. medianus "of or that is in the middle,"
→ median. 1) Miyângin "the middle; middle-sized; the middle pearl in a string," from
miyân, → middle, + -gin a suffix forming adjectives of
possession. |
mean anomaly nâsâni-ye miyângin Fr.: anomalie moyenne The angle between the periapsis of an orbit and the position of a hypothetical body that orbits in the same period as the real one but at a constant mean angular velocity. |
mean catalog place jâ-ye miyângin-e kâtâlogi Fr.: position catalogue moyenne That point on the → celestial sphere at which an object would be seen from the solar system → barycenter affected by the → e-terms → aberration. |
mean daily motion jenbeš-e ruzâne-ye miyângin (#) Fr.: mouvement diurne moyen The average movement of a body along its orbit in one day, usually expressed in degrees. |
mean element bonpâr-e miyângin Fr.: élément moyen An element of an adopted reference orbit that approximates the actual, perturbed orbit. Mean elements may serve as the basis for calculating perturbations. |
mean equator hamugâr-e miyângin Fr.: équateur moyen The orientation the Earth's equator would have if the nutation was subtracted. |
mean equinox hamugân-e miyângin Fr.: équinoxe moyen A fictitious equinox whose position is that of the vernal equinox at a particular epoch with the effect of nutation removed. |
mean free path puyeš-e âzâd-e miyângin (#) Fr.: libre parcours moyen The mean distance which a particle moves between two successive collisions with other particles of the medium. Mean free path is inversely proportional to the number of particles per cm^{3} (n), and the collision → cross section (σ). In the case of a gas with molecules having a diameter of d, the cross section is equal to the area of a circle of radius d, i.e. σ = πd^{2}, and the mean free path is given by: l = 1/(nσ). Taking into account the relative velocity distribution of the colliding molecules, l = 1/(√2 . nσ). For a gas at one atmosphere pressure and room temperature, the average distance between molecules is roughly 3.5 × 10^{-7} cm, that is some 35 times the diameter of a molecule. Taking the gas density n = 2.4 × 10^{14} molecules cm^{-3}, and a typical diameter d = 2 × 10^{-8} cm for a molecule, the mean free path is 3.3 × 10^{-5} cm. This means that the average distance between collisions is about 95 times the average distance between molecules. Puyeš, verbal noun of puyidan "to run, trot; wander," from Mid.Pers. pôy-, pwd- "to run;" cf. Gk. speudein "to hasten;" Lith. spudinti; âzâd, → free; miyângin, → mean. |
mean life zist-e miyângin Fr.: vie moyenne The average amount of time an unstable radioisotope exists before it decays, It is equal to 1.44 times the half-life. |
mean molecular weight vazn-e molekuli-ye miyângin (#) Fr.: poids moléculaire moyen The total atomic or molecular weight divided by the total number of particles. For instance, the mean molecular weight of a plasma of pure ionized ^{4}He would be 4 (the atomic mass number) divided by 3, the total number of particles (1 nucleus plus 2 electrons), i.e. 4/3. |
mean moon mâh-e miyângin (#) Fr.: lune moyenne A fictitious Moon that has the same average motion as the true Moon but that is not subject to any gravitational perturbations by other bodies. |
mean motion jonbeš-e miyângin (#) Fr.: mouvement moyen The average angular velocity of a satellite in an elliptical orbit. |
mean parallax didgašt-e miyângin Fr.: parallaxe moyenne The parallax, derived by means of statistical studies of brightness and motions, for a large group of stars whose individual parallaxes cannot be measured. |
mean place jâ-ye miyângin Fr.: position moyenne An object's celestial position as determined for a given mean equator and equinox. → mean position. |
mean pole qotb-e miyângin Fr.: pôle moyen The direction of the Earth's axis at a particular epoch if the nutation is ignored. |
mean position neheš-e miyângin Fr.: position moyenne Same as → mean place. |