Osgood, William F. (William Fogg), 1864-1943, Graustein, William C. (William Caspar), 1888-1941, joint author · New York : The Macmillan Company · leaf 573
wnwards. The (z, ic)-plane contains the pommeland the (y, 2;)-plane, thestirrups. The surface can bestbe plotted by drawingthe sections parallel to avertical coordinate plane,for example, the (y, z)-plane. These sectionsare all parabolas openingdownwards and havingtheir vertices on the parabola in… … Fig. 8 QUADRIC SURFACES 555 the vertical coordinate planes. The line is known as the axis,and the planes as the principal planes. The sections by theprincipal planes are called the principal sections, and the point0, the vertex. EXERCISES Construct accurately the following paraboloids. 9 4 9 4 3.…
