/MCJI 



I .; 



injection of c/( - 

 in turn gives 



/ ' / ' i & D V* D 



I / 



(co8a=./"j ./"p a oos/9"yj y^, 

 iimi, finally, 



These equations give the required direction angles of 



30& The point which divides in a given ratio the straight 



from one point to another. Let 



y,, *!> andP s =(r, 

 given points, and let 



'r y* f a) k 6 a t ^ ir ^ P n * 

 divides the line PjP, in the 





given ratio I, so that ,/ f - . ^ ~ A/; 



.^ IM " 

 Let PjP, a r and 



i by Art. 204, if , A 7 1*> tne direction angles f l\I' r 



COS U : : 



-. % 



- T, c/, m, 



'"i 



'"- 



Similarly, 



'l * = "- : = t a. 



in, m_, 



U \\ill IH^ noticed, as in the similar prohlom in Part I. 

 :jo, that if J\ divides the line externally, tin* ratio "i 

 l>e negat 1 the above formulas still a; 



