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CISSOID (from the Gr. rcunr6s, ivy, a...

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Originally appearing in Volume V06, Page 393 of the 1911 Encyclopedia Britannica.
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CISSOID (from the Gr. rcunr6s, See also:ivy, and ethos, See also:form)  , a See also:curve invented by the See also:Greek mathematician Diocles about 18o B.C., for the purpose of constructing two mean proportionals between two given lines; and in See also:order to solve the problem of duplicating the See also:cube . It was further investigated by See also:John See also:Wallis, Christiaan See also:Huygens (who determined the length of any arc in 1657), and See also:Pierre de See also:Fermat (who evaluated the See also:area between the curve and its asymptote in 1661) . It is constructed in the following manner . Let APB be a semicircle, BT the tangent at B, and See also:APT a See also:line cutting the circle in P and BT at T; take a point Q on AT so that AQ always equals PT; then the See also:locus of Q is the See also:cissoid . See also:Sir See also:Isaac See also:Newton devised the following See also:mechanical construction . Take a See also:rod LMN See also:bent at right angles at M, such that MN=AB; let the See also:leg LM always pass through a fixed point 0 on AB produced such that OA = CA, where C is the See also:middle point of AB, and cause N to travel along the line perpendicular to AB at C; then the midpoint of MN traces the cissoid . The curve is symmetrical about the See also:axis of x, and consists of two See also:infinite branches asymptotic to the line BT and forming a See also:cusp' at the origin . The cartesian See also:equation, when A is the origin and AB = 2a, is y2(2a—x)=x3; the polar equation is r=2a See also:sin B tan B . The cissoid is the first See also:positive pedal of the See also:parabola y2+8ax=o for the vertex, and the inverse of the parabola y2=8ax, the vertex being the centre of See also:inversion, and the semi-latus rectum the See also:constant of inversion . The area between the curve and its asymptote is 3aa2, i.e. three times the area of the generating circle . The See also:term cissoid has been given in See also:modern times to curves generated in similar manner from other figures than the circle, and the See also:form described above is distinguished as the cissoid of Diocles . A cissoid See also:angle is the angle included between the See also:concave sides of two intersecting curves; the See also:convex sides include the sistroid angle .

See John Wallis, Collected See also:

Works, vol. i . ; T . H . Eagles, See also:Plane Curves (1885) . CIS-See also:SUTLEJ STATES, the See also:southern portion of the See also:Punjab, See also:India . The name, now obsolete, came into use in 1809, when the See also:Sikh chiefs See also:south of the Sutlej passed under See also:British See also:protection, and was generally applied to the See also:country south of the Sutlej and See also:north of the See also:Delhi territory, bounded on the E. by the Himalayas, and on the W. by See also:Sirsa See also:district . Before 1846 the greater See also:part of this territory as See also:independent, the chiefs being subject merely to See also:control from a See also:political officer stationed at See also:Umballa, and styled the See also:agent of the See also:governor-See also:general for the Cis-Sutlej states . After the first Sikh See also:War the full See also:administration of the territory became vested in this officer . In 1849 occurred the See also:annexation of the Punjab, when the Cis-Sutlej states commissionership, comprising the districts of Umballa, Ferozepore, See also:Ludhiana, See also:Thanesar and See also:Simla, was incorporated with the new See also:province . The name continued to be applied to this See also:division until 1862, when, owing to Ferozepore having been transferred to the See also:Lahore, and a part of Thanesar to the Delhi division, it ceased to be appropriate . Since then, the See also:tract remaining has been known as the Umballa division . See also:Patiala, See also:Jind and See also:Nabha were appointed a See also:separate political agency in 1901 .

Excluding See also:

Bahawalpur, for which there is no political agent, and See also:Chamba, the other states are grouped under the commissioners of Jullunder and Delhi, and the See also:superintendent of the Simla See also:hill states .

End of Article: CISSOID (from the Gr. rcunr6s, ivy, and ethos, form)
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