Leonhard Euler · 1748 · Internet Archive
Introductio in analysin infinitorum
All 320 leaves · leaf 309
Transcription
IN RADICIBUS ÆQUATION. INDAGAND. 279
fit, satis est perspicuum. Ex Factoribus enim denominatoris $1 - \alpha z - \beta z^2 - \gamma z^3 - \delta z^4 - \&c.$, cognitis facile assignantur radices æquationis hujus
$1 - \alpha z - \beta z^2 - \gamma z^3 - \delta z^4 - \&c. = 0$,
ita ut, si Factor fuerit $1 - pz$, hujus æquationis radix una futura fit $z = \frac{1}{p}$. Cum igitur ex Serie recurrente reperiatur maximus numerus $p$, indidem obtinebitur minima radix æquationis $1 - \alpha z - \beta z^2 - \gamma z^3 - \&c. = 0$. Vel, si ponatur $z = \frac{1}{x}$ ut prodeat hæc æquatio
$x^m - \alpha x^{m-1} - \beta x^{m-2} - \gamma x^{m-3} - \&c. = 0$,
ejusdem methodi ope eruitur maxima hujus æquationis radix $x = p$.
338. Si igitur proponatur æquatio hæc
$x^m - \alpha x^{m-1} - \beta x^{m-2} - \gamma x^{m-3} - \&c. = 0$,
quæ omnes radices habeat reales & inter se inæquales, harum radicum maxima sequenti modo reperietur. Formetur ex coëfficientibus hujus æquationis fractio
$\frac{a+bz+cz^2+dz^3+\&c.}{1-\alpha z - \beta z^2 - \gamma z^3 - \delta z^4 - \&c.}$
Hincque formetur Series recurrens, assumendo pro arbitrio numeratorem, seu, quod eodem redit, assumendo pro libitu terminos initiales; quæ sit
$A+Bz+Cz^2+Dz^3+ \dots + Pz^n + Qz^{n+1}$
dabitque fractio $\frac{Q}{P}$ valorem radicis maximæ $x$ pro æquatione proposita, eo propius, quo major fuerit numerus $n$.
EXEM-
This text was produced by machine and has not been corrected by hand. Where it matters, read the scan. Confidence is the model's own, not an external check.