H 



Ellcry Williams DavLs 



Let the first change f\ to /$ and .' . fi back to/i, the second change 

 f\ to/3, while the third changes f\ to f\. 



We get- 



SC 2 2V f\ — 



nc 2 w ns l w 



ccTzv cos 2 6sd 2 w 



■ — sec 2 9cs 2 w fa — cos 2 Qsc 1 w 



se^dd^w dc 2 w 



/3' 



cscdns 2 w — csc 2 Bds 2 w 

 nd 2 w fs dn 2 w 



—sin 2 6sd 2 w shPQsrfw 



csc 2 6dc 2 w — cofOnc^w 

 sec 2 6d?i 2 w f± cos 2 6>id 2 w 



— tan 2 Qcn 2 tv sin' 2 6cd 2 w 



The substitutions connecting the forms in each set are shown 

 below. 



s r 



•,m3 



Ifi' 



244 



