Leonhard Euler · 1748 · Internet Archive
Introductio in analysin infinitorum
All 320 leaves · leaf 286
Transcription
258 DE PARTITIONE
LIB. I. $1+x+2x^2+3x^3+5x^4+7x^5+11x^6+15x^7+22x^8 \text{ \&c.}$,
in qua quilibet coëfficiens indicat, quot variis modis Exponens Potestatis adjunctæ per additionem produci queat ex numeris integris, five æqualibus five inæqualibus. Scilicet ex termino $11x^6$ cognoscitur numerum $6$ undecim modis par additionem numerorum integrorum produci posse, qui sunt
$6=6$
$6=5+1$
$6=4+2$
$6=4+1+1$
$6=3+3$
$6=3+2+1$
$6=3+1+1+1$
$6=2+2+2$
$6=2+2+1+1$
$6=2+1+1+1+1$
$6=1+1+1+1+1+1$
ubi quoque notari debet, ipsum numerum propositum, cum in Serie numerorum $1, 2, 3, 4, 5, 6, \text{ \&c.}$, proposita contineatur, unum modum præbere.
306. His in genere expositis, diligentius inquiramus in modum hanc compositionum multitudinem inveniendi. Ac primo quidem consideremus eam ex numeris integris compositionem, in qua numeri tantum diversi admittuntur, quam prius commemoravimus. Sit igitur in hunc finem proposita hæc expressio
$Z=(1+xz)(1+x^2z)(1+x^3z)(1+x^4z)(1+x^5z) \text{ \&c.}$,
quæ evoluta & secundum Potestates ipsius $z$ digesta præbeat
$Z = 1 + Pz + Qz^2 + Rz^3 + Sz^4 + Tz^5 + \text{ \&c.}$,
ubi methodus desideratur has ipsius $x$ Functiones $P, Q, R, S, T, \text{ \&c.}$, expedite inveniendi, hoc enim pacto quæstioni propositæ convenientissime satisfiet.
307. Patet autem, si loco $z$ ponatur $xz$, prodire
$(1+$
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