PLATE XK 



55. Sin^sin|-y =sin xsm|-x. 



■(iT^So 



O ° O <^ X) " o ( X ) o o 

 56,. Sinysin|-y=sinxsin|-x. 



58. Siny sin|-y = sm xsin fx. 



PiniJersontlt Crisa7idl^e\\'TIa\'erv,C 



