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# Title: [Lectiones XVIII, Cantabrigiae in Scholis publicis habitae] Lectiones XVIII, Cantabrigiæ in Scholis publicis habitæ (shelfmarks Leibn. Marg. 0; ZEN Leibn. Marg. 0)
# Folio 89, page id 797435492:0141
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L E C Y. ZIII.
Y. Si tuerie AHIE CR, retractus N a cum AC retro tractus FI∞. 132
conveniet.
NaM C R = 3 N R. (ut in priore casu).
20 Etiam hiC(I A ZI = CR, retractus N a At ipA A C paralle
Iu5.
Nam erir C K = N K. quod in hoc casunisi R infinitè distet con-
tingere nequit.
3. Si ANV = CR; retractus Na prorsim excurrens axi OC.
currie.
Nam HiCC RE NR.
4. Si AB I C R; omnes refracti directe progredientes ad A C Fig. 133
conversunt. Fric enim quivis incidens AN 1 C R.
5. Ouum AN = CR, evidens est omnes arcui B N incidentes
retrorsum vertus C A retractos convergere; omnes autem ad partes
NT cadentes antrorlum versus C. B retringi.
XII. Elinc apparer sub ictis duobus generalibus casibustres a diver(o Fig. 134
puncti radiancis interrallo subnascentes speciales casus comprehendi; X35, 136.
nempe vel omnes ab axe post retractionem progredientes diversunt,
vel omnes ad iplum conrersunt, rel aliqui dirergunt, alii convergunt,
his intercedente medio quodam ad illum parallelo. qua subnotâsse
discrimina videbatur operx prerium ac determinasse. Subdimus
etiam quoad reliquos generales casus simplicius sele rem habere.
Scilicet eodem semper modo: Omnes enim ad carum densius inci-
dentium retracti directe procedentes ab axe divergunt; Ut _ omnes
eorum, qui conrexo ratiori impunsunt; id quod e generalistimis re-
tractionum lesibus immediate sequitur, ee e simplice secundum illas
lincarum ductu dilucescit. Eiis admonitis in orbicam regressi peroi-
MUS.
XIII. F praemisso Theoremate non dificile conficitur hoc Problema:
Dato in axe puncto R, retractum delignare, qui per hociplum tran-
Pear. II
Hlocnempe pacto. Reperiatur punctum (7, WE SIE R O. AC:: Lect. 10
CR. C R. item AaE G F. F A:: C R. CR. C:: X G. A(). TUm Num. 25.
centro F, interrallo F. C de Ccribatur circulus retringentem intersecans Fig. 137a
2d N; erit connexa N R incidentis A H retractus.
Nam ducatur FN; _ Ob RC. A G:: (F. F A. erit permu-
tatim RC. GF:: AC. F A. diridendoque RF. GF:: GF. F A.
hoc est KF. PHI:: FN. F A. Quare criangula RPH, N F A
aCiri-