FORMFLAS BIFFKRKNT. RATIONJIES. 151 



e^l^^ _ ^ et 2^=^ - >,, hincqiie orientur 

 fequentes liiiae formae pro ficftoribus trinomialibus quae- 

 fitis 



!>- <^* - 2 .V f/ V <^ . cof. k. i!i![ -\- XX f yy 



p y^— 2,v -^ yY\. cof. A . i^ --}- A,\v -|V yy 



qui , quoties fiunt c]uadrata , radices praebent fimpliccs realos, 

 cctcris cafibus fidor^s triHomiales reiiiltant. Sit iam pro- 

 pofita ifta exprcllio 



III. a-f- ^x^-yx^"" 



in qna femper eft (S^-H^ay quantitas pofitiiia. Praebet 



autem cafus ($> — \^ vnum valorem pofitiuum pro/" 



__ , t^-t- v^- _ . ait;ei.qi,e cafus Cp — i — ;j-^ pariter 



vnum / — 77 ■• Ponatur ■-■ ^- — c; 



et •=i^^^^--=t±52i — ^ ^ atqiie fequentes duae formulae da- 

 bunt omnes fidores reales tam fimplices (quando (cilicet 

 fiunt quadrata ) quam trinomiales : 



-[V ^* — 2.V f' V (^. cof A . ^ -I- .v.v y- y V 

 f ^* - cx f y >i . cof A . (i^-ill -f. XX fyy 



§.33- Qiiartiis cafus , quo fponte fit p*>>4«y,eft 



haec forma 



IV. a-(3.v"-yA;^'* 



Hic itcrum cafus (^——~ vnum praebet cafum pofiti- 



vum pro /" - -^^^-^^ alterque cafus Cp - ^^ 



pariter vnum /" z=. ^^'|^"-1'. Ponatur ergo iP±^fai«15 



rr: ^ et f '^*°''^ - — v) , atque omncs fadores formuiae 



R 2. pro- 



