44-40.J nn. A.v'.i//"V of A I 66 



!..-!i, in trundle AOJ\ angle OPA in * right angle, 

 - P% and OP:OA-**e\ t.t. 9 



p : 2 r COB ; 

 1..M., />-2roos0. . . (1) 



satisfied ly lli }n,l,ir ronrdin.ites of every 

 MII tl,. satisfied by tin- -.onli nates 



. MIICO angle AQO U not a 

 II'}. (1) is tin- equation of this circle 



EXERCISES 



1. ' aquation of the straight lin<> through the two points (1,7) 

 and ( :.-.i-i, the points (-2, 5) and (3, 8). Which is the pusi- 



2. Find the equation of iho Mraight line thn.u-h the two poinU ( . 

 nti.l Through what other point does this line pass? Doss 

 the equation show this fact? 



3. Find the equa he straight lino thnnii;: -7), 

 asking an angle of 45 with the x-axis ; making the angle -45 u it I, 



4. Find the equation of the line throu-1, tl,. jN.int (-rt, -J). and 

 making the angle 150 with the x- 



5. Construct the circle whose equation !s p = 10 cos & 



G. With rectangular coordinates, find the equation <>f the circle of 

 radius u, which paaae* Ihn.u-h th. ori-in, and haa its center on the 

 x-axi*. In its poaitiro aide outside or inside? 



46. Equation of locus traced by a moving point. In 

 '. MH given above, the geometric figure in each case waa 

 known; and, in <>l>tuining its equation, uae waa 

 tin* knuwn pnprrt'us of similar triangles, triangles 

 viU-il in a | !, and tri^mMim'trir functions. In 



only a few cases, however, is tin* rurv- so r..;u|.]. 



in a large class of important problrn irvr 



TAX. AJC. OKM. 



