A history of Greek mathematics Vol.II from Aristarchus to Diophantus by Heath, Thomas Little, Sir, 1921
MACEDONIA is GREECE and will always be GREECE- (if they are desperate to steal a name, Monkeydonkeys suits them just fine) ΚΑΤΩ Η ΣΥΓΚΥΒΕΡΝΗΣΗ ΤΩΝ ΠΡΟΔΟΤΩΝ!!! ΦΕΚ,ΚΚΕ,ΚΝΕ,ΚΟΜΜΟΥΝΙΣΜΟΣ,ΣΥΡΙΖΑ,ΠΑΣΟΚ,ΝΕΑ ΔΗΜΟΚΡΑΤΙΑ,ΕΓΚΛΗΜΑΤΑ,ΔΑΠ-ΝΔΦΚ, MACEDONIA,ΣΥΜΜΟΡΙΤΟΠΟΛΕΜΟΣ,ΠΡΟΣΦΟΡΕΣ,ΥΠΟΥΡΓΕΙΟ,ΕΝΟΠΛΕΣ ΔΥΝΑΜΕΙΣ,ΣΤΡΑΤΟΣ, ΑΕΡΟΠΟΡΙΑ,ΑΣΤΥΝΟΜΙΑ,ΔΗΜΑΡΧΕΙΟ,ΝΟΜΑΡΧΙΑ,ΠΑΝΕΠΙΣΤΗΜΙΟ,ΛΟΓΟΤΕΧΝΙΑ,ΔΗΜΟΣ,LIFO,ΛΑΡΙΣΑ, ΠΕΡΙΦΕΡΕΙΑ,ΕΚΚΛΗΣΙΑ,ΟΝΝΕΔ,ΜΟΝΗ,ΠΑΤΡΙΑΡΧΕΙΟ,ΜΕΣΗ ΕΚΠΑΙΔΕΥΣΗ,ΙΑΤΡΙΚΗ,ΟΛΜΕ,ΑΕΚ,ΠΑΟΚ,ΦΙΛΟΛΟΓΙΚΑ,ΝΟΜΟΘΕΣΙΑ,ΔΙΚΗΓΟΡΙΚΟΣ,ΕΠΙΠΛΟ, ΣΥΜΒΟΛΑΙΟΓΡΑΦΙΚΟΣ,ΕΛΛΗΝΙΚΑ,ΜΑΘΗΜΑΤΙΚΑ,ΝΕΟΛΑΙΑ,ΟΙΚΟΝΟΜΙΚΑ,ΙΣΤΟΡΙΑ,ΙΣΤΟΡΙΚΑ,ΑΥΓΗ,ΤΑ ΝΕΑ,ΕΘΝΟΣ,ΣΟΣΙΑΛΙΣΜΟΣ,LEFT,ΕΦΗΜΕΡΙΔΑ,ΚΟΚΚΙΝΟ,ATHENS VOICE,ΧΡΗΜΑ,ΟΙΚΟΝΟΜΙΑ,ΕΝΕΡΓΕΙΑ, ΡΑΤΣΙΣΜΟΣ,ΠΡΟΣΦΥΓΕΣ,GREECE,ΚΟΣΜΟΣ,ΜΑΓΕΙΡΙΚΗ,ΣΥΝΤΑΓΕΣ,ΕΛΛΗΝΙΣΜΟΣ,ΕΛΛΑΔΑ, ΕΜΦΥΛΙΟΣ,ΤΗΛΕΟΡΑΣΗ,ΕΓΚΥΚΛΙΟΣ,ΡΑΔΙΟΦΩΝΟ,ΓΥΜΝΑΣΤΙΚΗ,ΑΓΡΟΤΙΚΗ,ΟΛΥΜΠΙΑΚΟΣ, ΜΥΤΙΛΗΝΗ,ΧΙΟΣ,ΣΑΜΟΣ,ΠΑΤΡΙΔΑ,ΒΙΒΛΙΟ,ΕΡΕΥΝΑ,ΠΟΛΙΤΙΚΗ,ΚΥΝΗΓΕΤΙΚΑ,ΚΥΝΗΓΙ,ΘΡΙΛΕΡ, ΠΕΡΙΟΔΙΚΟ,ΤΕΥΧΟΣ,ΜΥΘΙΣΤΟΡΗΜΑ,ΑΔΩΝΙΣ ΓΕΩΡΓΙΑΔΗΣ,GEORGIADIS,ΦΑΝΤΑΣΤΙΚΕΣ ΙΣΤΟΡΙΕΣ, ΑΣΤΥΝΟΜΙΚΑ,ΦΙΛΟΣΟΦΙΚΗ,ΦΙΛΟΣΟΦΙΚΑ,ΙΚΕΑ,ΜΑΚΕΔΟΝΙΑ,ΑΤΤΙΚΗ,ΘΡΑΚΗ,ΘΕΣΣΑΛΟΝΙΚΗ,ΠΑΤΡΑ, ΙΟΝΙΟ,ΚΕΡΚΥΡΑ,ΚΩΣ,ΡΟΔΟΣ,ΚΑΒΑΛΑ,ΜΟΔΑ,ΔΡΑΜΑ,ΣΕΡΡΕΣ,ΕΥΡΥΤΑΝΙΑ,ΠΑΡΓΑ,ΚΕΦΑΛΟΝΙΑ, ΙΩΑΝΝΙΝΑ,ΛΕΥΚΑΔΑ,ΣΠΑΡΤΗ,ΠΑΞΟΙ
MACEDONIA is GREECE and will always be GREECE- (if they are desperate to steal a name, Monkeydonkeys suits them just fine)
ΚΑΤΩ Η ΣΥΓΚΥΒΕΡΝΗΣΗ ΤΩΝ ΠΡΟΔΟΤΩΝ!!!
ΦΕΚ,ΚΚΕ,ΚΝΕ,ΚΟΜΜΟΥΝΙΣΜΟΣ,ΣΥΡΙΖΑ,ΠΑΣΟΚ,ΝΕΑ ΔΗΜΟΚΡΑΤΙΑ,ΕΓΚΛΗΜΑΤΑ,ΔΑΠ-ΝΔΦΚ, MACEDONIA,ΣΥΜΜΟΡΙΤΟΠΟΛΕΜΟΣ,ΠΡΟΣΦΟΡΕΣ,ΥΠΟΥΡΓΕΙΟ,ΕΝΟΠΛΕΣ ΔΥΝΑΜΕΙΣ,ΣΤΡΑΤΟΣ, ΑΕΡΟΠΟΡΙΑ,ΑΣΤΥΝΟΜΙΑ,ΔΗΜΑΡΧΕΙΟ,ΝΟΜΑΡΧΙΑ,ΠΑΝΕΠΙΣΤΗΜΙΟ,ΛΟΓΟΤΕΧΝΙΑ,ΔΗΜΟΣ,LIFO,ΛΑΡΙΣΑ, ΠΕΡΙΦΕΡΕΙΑ,ΕΚΚΛΗΣΙΑ,ΟΝΝΕΔ,ΜΟΝΗ,ΠΑΤΡΙΑΡΧΕΙΟ,ΜΕΣΗ ΕΚΠΑΙΔΕΥΣΗ,ΙΑΤΡΙΚΗ,ΟΛΜΕ,ΑΕΚ,ΠΑΟΚ,ΦΙΛΟΛΟΓΙΚΑ,ΝΟΜΟΘΕΣΙΑ,ΔΙΚΗΓΟΡΙΚΟΣ,ΕΠΙΠΛΟ, ΣΥΜΒΟΛΑΙΟΓΡΑΦΙΚΟΣ,ΕΛΛΗΝΙΚΑ,ΜΑΘΗΜΑΤΙΚΑ,ΝΕΟΛΑΙΑ,ΟΙΚΟΝΟΜΙΚΑ,ΙΣΤΟΡΙΑ,ΙΣΤΟΡΙΚΑ,ΑΥΓΗ,ΤΑ ΝΕΑ,ΕΘΝΟΣ,ΣΟΣΙΑΛΙΣΜΟΣ,LEFT,ΕΦΗΜΕΡΙΔΑ,ΚΟΚΚΙΝΟ,ATHENS VOICE,ΧΡΗΜΑ,ΟΙΚΟΝΟΜΙΑ,ΕΝΕΡΓΕΙΑ, ΡΑΤΣΙΣΜΟΣ,ΠΡΟΣΦΥΓΕΣ,GREECE,ΚΟΣΜΟΣ,ΜΑΓΕΙΡΙΚΗ,ΣΥΝΤΑΓΕΣ,ΕΛΛΗΝΙΣΜΟΣ,ΕΛΛΑΔΑ, ΕΜΦΥΛΙΟΣ,ΤΗΛΕΟΡΑΣΗ,ΕΓΚΥΚΛΙΟΣ,ΡΑΔΙΟΦΩΝΟ,ΓΥΜΝΑΣΤΙΚΗ,ΑΓΡΟΤΙΚΗ,ΟΛΥΜΠΙΑΚΟΣ, ΜΥΤΙΛΗΝΗ,ΧΙΟΣ,ΣΑΜΟΣ,ΠΑΤΡΙΔΑ,ΒΙΒΛΙΟ,ΕΡΕΥΝΑ,ΠΟΛΙΤΙΚΗ,ΚΥΝΗΓΕΤΙΚΑ,ΚΥΝΗΓΙ,ΘΡΙΛΕΡ, ΠΕΡΙΟΔΙΚΟ,ΤΕΥΧΟΣ,ΜΥΘΙΣΤΟΡΗΜΑ,ΑΔΩΝΙΣ ΓΕΩΡΓΙΑΔΗΣ,GEORGIADIS,ΦΑΝΤΑΣΤΙΚΕΣ ΙΣΤΟΡΙΕΣ, ΑΣΤΥΝΟΜΙΚΑ,ΦΙΛΟΣΟΦΙΚΗ,ΦΙΛΟΣΟΦΙΚΑ,ΙΚΕΑ,ΜΑΚΕΔΟΝΙΑ,ΑΤΤΙΚΗ,ΘΡΑΚΗ,ΘΕΣΣΑΛΟΝΙΚΗ,ΠΑΤΡΑ, ΙΟΝΙΟ,ΚΕΡΚΥΡΑ,ΚΩΣ,ΡΟΔΟΣ,ΚΑΒΑΛΑ,ΜΟΔΑ,ΔΡΑΜΑ,ΣΕΡΡΕΣ,ΕΥΡΥΤΑΝΙΑ,ΠΑΡΓΑ,ΚΕΦΑΛΟΝΙΑ, ΙΩΑΝΝΙΝΑ,ΛΕΥΚΑΔΑ,ΣΠΑΡΤΗ,ΠΑΞΟΙ
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
HERONIAN INDETERMINATE EQUATIONS 445<br />
number 3 is <strong>of</strong> course only an illustration, and the problem is<br />
equivalent <strong>to</strong> the solution <strong>of</strong> the equations<br />
(1) u + v — n(x + y))<br />
(2) xy = n.uv )<br />
The solution given in the text is equivalent <strong>to</strong><br />
x=2n 3 — 1, y — 2ti 3,<br />
u — n(4n<br />
3<br />
— 2),<br />
v — n<br />
Zeuthen suggests that the solution may have been obtained<br />
thus. As the problem is indeterminate, it would be natural<br />
<strong>to</strong> start with some hypothesis, e.g. <strong>to</strong> put v = n. It would<br />
follow <strong>from</strong> equation (1) that u is a multiple <strong>of</strong> n, say nz.<br />
We have then<br />
x + y = 1 + z,<br />
while, <strong>by</strong> (2), xy — n 3 z,<br />
whence xy = n 3 (x + y) — n 3 ,<br />
or (x — n 3 ) (y — n 3 ) = n 3 (n 3 — 1 ).<br />
An obvious solution is<br />
which gives z — 2 n 3 — 1 + 2 ^ :i<br />
x — n 3 = n 3 — 1, y — n 3 — it 3 ,<br />
— 1 = 4?i 3 — 2, so that<br />
u = ttig<br />
— 7i (4 ii<br />
3 — 2).<br />
<strong>II</strong>. The second is a similar problem about two rectangles,<br />
equivalent <strong>to</strong> the solution <strong>of</strong> the equations<br />
(1) x + y = u + v<br />
(2) or?/ = 7i .<br />
m?J<br />
and the solution given in the text is<br />
|<br />
x + y = u + v = n 3 — 1, (3)<br />
u=n— 1, v = 7i (^2 — 1)^<br />
a> = n 2 -l, 2/==7i 2 (7i~l))<br />
In this case trial may have been made <strong>of</strong> the assumptions<br />
v = nx, y = n 2 u,<br />
446 ALGEBRA: DIOPHANTUS OF ALEXANDRIA<br />
when equation (1)<br />
would give<br />
(n — \)x = (ri z — l)u,<br />
a solution <strong>of</strong> which is x = n 2 — 1, u = n — 1<br />
<strong>II</strong>I. The fifth problem is interesting in one respect. We are<br />
asked <strong>to</strong> find a right-angled triangle (in rational numbers)<br />
with area <strong>of</strong> 5 feet. We are <strong>to</strong>ld <strong>to</strong> multiply 5 <strong>by</strong> some<br />
square containing 6 as a fac<strong>to</strong>r, e.g. 36. This makes 180,<br />
and this is the area <strong>of</strong> the triangle (9, 40, 41). Dividing each<br />
sicle <strong>by</strong> 6, we have the triangle required. The author, then,<br />
is aware that the area <strong>of</strong> a right-angled triangle with sides in<br />
whole numbers is divisible <strong>by</strong> 6. If we take the Euclidean<br />
formula for a right-angled triangle, making the sides a . mn,<br />
a . ^(m — 2 n<br />
2), a . %(m 2 + n 2 ), where a is any number, and m, n<br />
are numbers which are both odd or both even, the area is<br />
\mn (m — n) (m + n)a<br />
2,<br />
and, as a matter <strong>of</strong> fact, the number mn(m — ri)(m + ri) is<br />
divisible <strong>by</strong> 24, as was proved later (for another purpose) <strong>by</strong><br />
Leonardo <strong>of</strong> Pisa.<br />
IV. The last four problems (10 <strong>to</strong> 13) are <strong>of</strong> great interest.<br />
They are different particular cases <strong>of</strong> one problem, that <strong>of</strong><br />
finding a rational right-angled triangle such that the numerical<br />
sum <strong>of</strong> its area and its perimeter is a given number. The<br />
author's solution depends on the following formulae, where<br />
a, b are the perpendiculars, and c the hypotenuse, <strong>of</strong> a rightangled<br />
triangle, S its area, r the radius <strong>of</strong> the inscribed circle,<br />
and s = %(a + b + c);<br />
S = rs = %ab, r + s = a + b, c — s — r.<br />
(The pro<strong>of</strong> <strong>of</strong> these formulae <strong>by</strong> means <strong>of</strong> the usual figure,<br />
namely that used <strong>by</strong> Heron <strong>to</strong> prove the formula<br />
is easy.)<br />
S = V{s(s-a)(s-b)(s-c)},<br />
Solving the first two equations, in order <strong>to</strong> find a and b,<br />
we have<br />
a<br />
\ = ±[r + s+ V{(r + s) 2 -8rs]],<br />
which formula is actually used <strong>by</strong> the author for finding a