Young, Charles A. (Charles Augustus), 1834-1908, Young, Anne Sewell, b. 1871., ed · Boston, New York [etc.] Ginn and Company · leaf 397
ection in this case is a hyperbola, GHK. If the plane ofthe section be produced upward, however, it encounters thecone produced, cutting out from it a second hyperbola,GHK, exactly like the original one, but turned in the oppo-site direction. The axis of the hyperbola is always reckonedas negative,… … Fig. 133. — The Conies. (c) When the angle madeby the cutting plane with theaxis is exactly equal to thecones semi-angle, the planewill be parallel to a planewhich is tangent to the coni-cal surface, and we then getthe special case of the parab-ola, which is, so to speak,the boundary or partition…
Astronomy · Constellations
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![An illustration from Nicolai Copernici Torinensis De reuolutionibus orbium coelestium, libri VI : Habes in hoc opere iam recens nato, & aedito, studiose lector, motus stellarum, tam fixarum, quàm erraticarum, cum ex ueteribus, tum etiam ex recentibus obseruationibus restitutos: & nouis insuper ac admirabilibus hypothesibus ornatos. Habes etiam tabulas expeditissimas, ex quibus eosdem ad quoduis tempus quàm facillime caculare poteris. Igitur eme, lege, fruere. [Line in Greek] (1543)](https://img.insideoutlibrary.com/img/200/ia-nicolaicopernici00cope-237-146.webp)
