Barrow, Isaac
,
Lectiones opticae & geometricae : in quibus phaenomenon opticorum genuinae rationes investigantur, ac exponuntur: et generalia curvarum linearum symptomata declarantur
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<
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. IX.</
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<
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<
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DB; </
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<
s
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">tranſeant verò per B lineæ EBE, FBF ità ad ſe relatæ, ut
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ductâ quâvis PG ad DB parallelâ, ſit perpetuò PF inter PG, PE
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eodem ordine deſignato media _Arithmeticè_; </
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<
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curvam EBE; </
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<
s
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VII.</
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imus ſupra) exponentes; </
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<
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que TB; </
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<
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VII.</
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cùm ergò ſit KG &</
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TB extra curvam FBF totam conſiſtere.</
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portionalis Geometrìcè (eodem ordine media nempe, quo fuit priùs
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Arithmeticè) eadem BT curvam FB F continget.</
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<
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7.</
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ce modo conſtructæ lineæ ſeſe mutuo contingunt ad B; </
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go M = 7; </
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<
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ſumptóque quovis in curva FBF puncto F; </
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tangens recta ſimili pacto deſignatur.</
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<
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curvam EXE in E, tum EX tangat curvam EBE in E; </
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<
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