Elements of Conic Sections: In Three Books: in which are Demonstrated the Principal Properties of the Parabola, Ellipse, and Hyperbola. By Richard Jack, ...

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Tho. Wal. and Tho. Ruddimans, 1742 - Conic sections - 331 pages

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Page 142 - If a tangent to the ellipse meet the transverse axis produced, and from the point of contact an ordinate be drawn to the same axis ; then is the semitransverse axis a mean proportional between the distances from the centre to the intersections of the axis by the ordinate and tangent. That is, (Fig.
Page 5 - Hz. tint if the distance of any point from the focus of a parabola, be equal > to the perpendicular drawn from it to the directrix, then shall that point fall in the curve of the parabola. Prop.
Page 62 - CD is common, the two sides AC, CD are equal to the two sides BC, CD; and the angle ACD is equal to the angle BCD, for each is right ; therefore the base AD is equal to the base DB. [i. 4] But equal straight lines cut...
Page 151 - The fum of the fquares of' any two conjugate diameters is equal to the fum of the fquares of the two axes.
Page 77 - C, and if the pin be moved round from any point until it return to tlîe place from whence it began to move, the thread being extended during the whole time of the revolution, the figure which the fmall pin by this revolution defcribes is called an ellipfe.
Page 29 - FCK is a right d. 47 i . angle, the fquare of FK is equal d to the fquares of FC, CK. for the fame reafon the fquare of FK is equal to the fquares of FB, BK. therefore the fquares of FC, CK are equal to the fquares of FB, BK, of which the fquare of FC is equal to the fquare of FB ; the remaining fquare of CK is therefore equal to the remaining fquare of BK, and e.
Page 1 - DEF a fquare, which let be placed in the fame plane in which the right line and point are., in fuch a manner that one fide of it, as...
Page 1 - EF, and the other extremity of it at the point C, and let part of the thread, as FG, be brought clofe to the...
Page 77 - ... extended by means of a fmall pin C, and if the pin be moved round from^ any point until it return to...
Page 129 - Line touches a Circle, and from the Point of Contact a Line be drawn perpendicular to the touching Line, the Center of the Circle ihall be in that Line.

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