; 





ia as represented in 1..;. 100, 



the yj- and *-plan<s but not 

 \\ith respect to the ry-plane. 

 Thin quadrio ia the elliptic 

 paraboloid, und may be con- 

 eeived as being generated by 

 a variable parabola which haa 

 , and moves 



always perpendicular to, a 

 fixed parabola, the axea of tho two parabolas bring parallel 

 and lying in the am* direct i*. Thin definition leads 

 directly to equn i J . 



, ery equation of the form AJ* -f II f 2 JV repre- 

 sents an elliptic parabolnM. If tlm two ponitive coefliciento 

 are equal, the quadrio ia a paraboloid of revolut Art. 



4)) - + * 



:ilarly, the equation ^-p- 



m m 



i . : : 



