Barrow, Isaac, Lectiones opticae & geometricae : in quibus phaenomenon opticorum genuinae rationes investigantur, ac exponuntur: et generalia curvarum linearum symptomata declarantur

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[81. Not.]
[82. Not.]
[83. Series quarta.]
[84. Not.]
[85. Series quinta.]
[86. Series ſexta.]
[87. Not.]
[88. Series ſeptima.]
[89. Not.]
[90. Series octava.]
[91. Series nona.]
[92. Not.]
[93. Series decima.]
[94. Series undecima.]
[95. Not.]
[96. Series duodecima]
[97. Series decima tertia]
[98. Not.]
[99. Laus DEOO ptimo Maximo. FINIS.]
[100. ERRATA]
[102. _Probl_. I.]
[103. _Probl_. II.]
[104. _Probl_. III.]
[106. _Theor_. I.]
[107. _Theor_. II.]
[108. _Theor_. III.]
[109. _Theor_. IV.]
[110. _Theor_. V.]
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fecans in N; & per N ducatur KN G;
Nam ob ANq = ACq - Vq. erit Vq = ACq - ANq.
Fig. 89.adeóque CBq. ACq - ANq: : (CBq. Vq: :) CK. AC.
quod, è præmonſtratis, reflectioni proprium eſt.
2. ltà quidem in hoc caſu; lt; AN; ACq + Vq; ut ſit ANq - ACq = Vq. Fiat 2 CK.
C B: : CB. F. & 2 CA. CB : : CB. E. ſumatúrque CQ = E
+ F.
& du@ta QN ad AC perpendicularis circulum ſecet in N. gt; AC; tum accipi debet
CQ = F - E;
&
IV. Intra caſus hos _Problema_, ceu videtis, facilè conſtruitur;
certè _δυσ@@νον_; vix ut aliud a
_Geometris_ hactenus attentatum difficilius reperiatur.
item ſemidiametro CA deſcribatur alter circulus AH G. tum à C
educantur rectæ quotvis CI circulum AICſecantes punctis I;
& per
A, I ductæ rectæ circulum AHGſecent punctis H;
X rectæ ducantur ipſas CI decuſſantes punctis N. per hujuſmodi
Fig. 90.puncta quævis deſignabilia tranſibit linea, _Problematis_ expoſiti ſo-
lutioni accommodata.
adeóque triangula AN I, HNIſibimet æqua-
lia prorſus &
æquiangala erunt; & ſpeciatim ang. INA = ang.
IN X.
V. _Problematum_ naturam magìs in propatulo collocantes à _Geometris_