-'-- -- j v' K* 



\t i- : M 



, , . . 



j a*'" SF -r F" 



.a?*- 1 ' (l) S- 1 w +-' 



Bj aquation* (-') an<l . 



8uUUtuUonin(l)giri + +! 

 o 1 6 1 c 1 



very algtOiraii- iu.iti..ii i.f tin- f-rm 



events ail ellips<>i<l. If two of the coefficient* of the 

 terms are equal it is an elkpeoid of revolu 



r ;ui olil.it. it.- .spheroid; and if the three co- 



> of tlio variaMo terms are e<jual. it is a sphere 

 H1), in 



jri |/i f 



229. The un-parted hyperboloid : equation fli + ^ - ^ = 1. 



:i till- tM|llatinll 



* _* 



. . . 



>1 lowing properties of iu locus may be derived : 

 (1 , : race on th<> s'/-\ i ellipse, with semi-axes 



a and b ; wliil<* i h- traces on the yi- and cr-planes are hyper- 

 bolas, having the semi-axes b ami <% < and a, respectively, 

 on jugate axes along the s-axis. 



traces on planes parallel to any coordinate plane 

 are .similar oonics, ellipses or hyperbolas, respectively 

 226). 



