Poats — Isogonic Transformation. 



47 



The equations for the second transformation are 

 x^= z sin 6 + X cos 6 



z^ "= z COS 6 — X sin 

 and equation (6) becomes, after assembling terms, 



+ sin2 



4" 2 tan a sin 6 cos 



+ sin^ - ^ ■ " 4- cos'^ 



+ 2 tan=» « 8in2 ^ 



+ sin 6 cos ^ 



4- tan a cos^ ^ 



-tanasin2(9 == B\ (7) 



— sin ^ cos 



— 2 tan'-* a sin ^ cos ^ 



4- cos^ 



— 2 tan a sin ^ cos d 



+ y' + z' 



-\- 2 tan^ a cos^ ^ 



+ 2x« 



Fig. 3. 



Making the coeificient of xz zero it is found that 



