Chapter 4: Geometry
Chapter 4: Geometry
Chapter 4: Geometry
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
FIGURE 4.39<br />
The ve non-degenerate real quadrics. Top left: ellipsoid. Top right: hyperboloid of two<br />
sheets (one facing up and one facing down). Bottom left: elliptic paraboloid. Bottom middle:<br />
hyperboloid of one sheet. Bottom right: hyperbolic paraboloid.<br />
Conversely, an equation of the form<br />
Ü ¾ · Ý ¾ · Þ ¾ ·¾Ü ·¾Ý ·¾Þ · ¼ (4.18.7)<br />
defines a sphere if ¾ · ¾ · ¾ ; the center is ´ µ<br />
Ô<br />
and the radius is<br />
¾ · ¾ · ¾ .<br />
1. Four points not in the same plane determine a unique sphere. If the points<br />
have coordinates ´Ü ½ Ý ½ Þ ½ µ, ´Ü ¾ Ý ¾ Þ ¾ µ, ´Ü ¿ Ý ¿ Þ ¿ µ, and ´Ü Ü Þ µ, the<br />
© 2003 by CRC Press LLC