L - — — y 



hicqHC fecandcim noftia praecepta ftaluamus p ~Ij±^ et 



q — ^'~'', unde fit p -h q — ~ et p — q~1^, hincque 

 2 — ^~'^, idcoqne diilerentiando 



quo valore fubftifuto impetramas 



5, 19. Cuni iam fit t -\ z ~ p v et r — z ~ q v l 

 eii!; pnmo ■ c z"=: i^ (/3 — 9), tum vero fumi^a cuboium dabit 



(i -I- z)' -f- ( 1 — z)^ — Z'^^ (p^ -j' q\ ~ 2 -\~ 6zz. 



3 



Qioniam igilur pofuimus Y (' ""^ ' zz) r v, erit 2;^rr i -h j 7,1; 

 quam ob rem habebimus p^ -' qf^ ( i --h o z z) ~. 2 -i- 6 z z , 

 confcquenter p^ iq- — r:. Denique vcro differentia cubo- 

 rum prabct (p^ q ) v^ — 6 - -+- :. z^; unde patet effe 3 s 

 H-i'^i(p'^ q') v''; at vero dilTcrentia quadratorum dat 

 {p p - qq)vv ~ ^z , unde lU z ~ \ v v {p }> — 9 q). 



§. ;-. S ibftitua;itur nTinc ifti valores loco z et 

 5 - -+- 2", atque- noftra formula' evadct" 



4(;3— .23) ' 



iibi crgo tantum binao litterae p et q occurrunt, quae ita 

 a fe invicem pendenl, -vt &i p' -\- q^ — 2 , ideoque difle- 

 rentiando p p J p -h q q d q ~ c , confequenter five d p ~ 

 -|.liL'7, five dq ~ -ZJLllP. 



