SPECIAL ALGEBRAIC TRANSFORMATIONS 



215 



<?/0B. Now <20^^<±2<50C + <COB; but <20C=± 

 <A0C=H<50A and <COB = 2<50A— <AOC, hence, on substi- 

 tution, 



<20^/.= <AOC=:6'. 



As the rhombes OA3B and OC?^D are equal it follows that 



011^=02. 



Thus, no matter how the linkage may be deformed and no matter 



id. 



how z may be assumed within its range, the point u represents e z. 



Fig. 3 



