Viviani, Vincenzo, De maximis et minimis, geometrica divinatio : in qvintvm Conicorvm Apollonii Pergaei

Table of contents

< >
[221.] THEOR. I. PROP. III.
[222.] LEMMA III. PROP. IV.
[223.] THEOR. II. PROP. V.
[224.] THEOR. III. PROP. VI.
[225.] LEMMA IV. PROP. VII.
[226.] THEOR. IV. PROP. VIII.
[227.] THEOR. V. PROP. IX.
[228.] SCHOLIVM.
[229.] THEOR. VI. PROP. X.
[230.] THEOR. VII. PROP. XI.
[231.] THEOR. VIII. PROP. XII.
[232.] THEOR. IX. PROP. XIII.
[233.] THEOR. X. PROP. XIV.
[234.] THEOR. XI. PROP. XV.
[235.] LEMMA V. PROP. XVI.
[236.] COROLL.
[237.] THEOR. XII. PROP. XVII.
[238.] THEOR. XIII. PROP. XVIII.
[239.] THEOR. XIV. PROP. XIX.
[240.] PROBL. I. PROP. XX.
[241.] MONITVM.
[242.] THEOR. XV. PROP. XXI.
[243.] PROBL. II. PROP. XXII.
[244.] PROBL. III. PROP. XXIII.
[245.] MONITVM.
[246.] THEOR. XVI. PROP. XXIV.
[247.] THEOR. XVII. PROP. XXV.
[248.] COROLL.
[249.] THEOR. XIIX. PROP. XXVI.
[250.] COROLL. I.
< >
page |< < (36) of 347 > >|
21836
Erigatur ex A contingenti A G perpendicularis A L, quæ axi 1188. pri-
mi huius.
ret in L, cui applicata A H, erit intercepta L H æqualis dimidio 2290. pri-
mi huius.
B I, hoc eſt dupla interuallo D B, (cum punctum D diſtet à vertice B
per quartam recti lateris partem ex hypoteſi) &
H G dupla eſt quoq; 3335. pri-
mi conic.
G B, quare, &
tota L G dupla eſt tota G D, ſiue L D æqualis D G, eſt-
que angulus L A G rectus, quare ſi
cum centro D, interuallo G, vel L
179[Figure 179] circulus deſcribatur, ipſe omnino
tranſibit per A;
vnde D A item æ-
qualis erit ipſis D G, D L, ſiue L G
erit dupla D A.
Et cum rectum axis
B D, ad rectum diametri A E, ſit vt
quadratum A H ad A G, vel 44Coroll.
24. huius.
triangulorum ſimilitudinem, vt qua-
dratum A L ad L G, vel vt recta
H L ad rectam L G (cum L A ſit
media proportionalis inter G L, L H)
ſumptis harum ſubduplis, erit rectũ
axis ad rectum diametri A E, vt D
B dimidium H L ad D A dimidium L G.
Quod erat demonſtrandum.
Vocatur autem punctum D, focus Parabolæ.
COROLL. I.
HInc cõſtat, omnes eductas à foco ad Parabolę peripheriam, ęqua-
ri quartæ parti rectorum, earum diametrorum, quarum vertices
ſint termini, quibus ipſæ eductæ ſectioni occurrunt:
rectum enim axis
B D ad rectum diametri A E, eſt vt D B ad D A, eſtque D B quarta pars
recti B I, quare, &
D A erit quarta pars recti lateris diametri A E, & D F
quadrans recti, diametri F R.
Vnde quò diametri ab axe remotiores
fuerint, eò ipſarum recta maiora erunt.
nam eſt D F maior D A, & c.
COROLL. II.
PAtet etiam, quamlibet eductam ex foco, ęquari aggregato ex inter-
uallo foci ab axis vertice, &
ſegmento axis inter verticem, & ap-
plicatam ex occurſu eductæ cum ſectione.
Oſtenſa eſt enim D A æqua-
lis D G, quæ æqualis eſt aggregato G B, cum B D, vel H B cum B D.
SCHOLIVM.
CVm demonſtratum ſit D G æqualem eſſe D A, erit angulus D G A,
vel parallelarum externus E A M, æqualis angulo D A G, ſed M
A G Parabolen contingit in A, quare ex Opticæ legibus, ſi E A fuerit
radius incidens ad concauam peripheriam A B C, ipſe A D erit 55Breuiùs,
& clariùs
quàm à
Vitellione
in 41. 9.
xus, atque omnes radij axi Parabolę æquidiſtantes in punctum D coi-
bunt;
vnde ſi ipſi fuerint ſonori, aut lucidi, ſimulque calidi, ibi

Text layer

  • Dictionary

Text normalization

  • Original

Search


  • Exact
  • All forms
  • Fulltext index
  • Morphological index