The Diophantine Equation x2 − Dy2 = z2 (Part II)

A Method of Generating Triples from Novel Equations

A new, general method for generating triples of the form (x,y,z) for the Diophantine equation x2 − Dy2 = z2, where D, is any integer greater than zero is being introduced here. The method produces a set of novel second order equations which generates Diophantine triples. These equations are listed below using the following table heading format:

δ1x y z δ2
a Da2 + n2 2na Dk2 - n2

where a is a generating number starting at zero, D is any integer greater than zero and (n2, 2n) are values taken from table A:

Table A (n2 & 2n values)
n2149162536496481100...
2n2468101214161820...

Since there are an infinite number of (n2, 2n) integers there are also an infinite number of tables which can be tabulated with their accompanying equations. A second sequential access is also possible using the δ1 and δ2 columns whose δ1δ1 and δ2δ2 are both 2 for all the tables. In addition,the triples which are generated may be present in primitive or non primitive form, and these non primitives can be converted to primitive forms by dividing out any common factors. When D equals one the Diophantine equation takes the form of x2 − y2 = z2. The calculations for this equation are shown in Tables I thru VIII. Note tha z may be negative at times, the reason being that the square root of z2 can take on the values ±z as is verified by the δ2 differences.

Table I
δ1x y z δ2
a a2 + 1 2a a2 - 1
010-1
11
1220
33
2543
55
31068
77
417815
99
5261024
1111
6371235
1313
7501448
Table II
δ1x y z δ2
a a2 + 4 4a a2 - 4
040-4
11
154-3
33
2880
55
313125
77
4201612
99
5292021
1111
6402432
1313
7532845

Next comes Tables III and IV.

Table III
δ1x y z δ2
a a2 + 9 6a a2 - 9
090-9
11
1106-8
33
21312-5
55
318180
77
425247
99
5343016
1111
6453627
1313
7584240
Table IV
δ1x y z δ2
a a2 + 16 8a a2 - 16
0160-16
11
1178-15
33
22016-12
55
32524-7
77
432320
99
541409
1111
6524820
1313
7655633

Next comes Tables V and VI.

Table V
δ1x y z δ2
a a2 + 25 10a a2 - 25
0250-25
11
12610-24
33
22920-21
55
33430-16
77
44140-9
99
550500
1111
6616011
1313
7747024
Table VI
δ1x y z δ2
a a2 + 36 12a a2 - 36
0360-36
11
13712-35
33
24024-32
55
34536-27
77
45248-20
99
56160-11
1111
672720
1313
7858413

Finally we have Tables VII and VIII.

Table VII
δ1x y z δ2
a a2 + 49 14a a2 - 49
0490-49
11
15014-48
33
25328-45
55
35842-40
77
46556-33
99
57470-24
1111
68584-13
1313
798980
Table VIII
δ1x y z δ2
a a2 + 64 16a a2 - 64
0640-64
11
16516-63
33
26832-60
55
37348-55
77
48064-48
99
58980-39
1111
610096-28
1313
7113112-15

Only eight triples, (x,y,z), were used in the calculation for the Diophantine equation x2 − y2 = z2 to get an idea of its versatility. Note that the tables produced can be expanded downward indefinitely. In addition, using the tables one can generate the appropriate equations that are useful for generating any triple in a table using a random access method or using δ1 and δ2 to access the (x,y,z)s sequentially.

This concludes Part II. Go to Part I. Go to Part III.

Go back to homepage.


Copyright © 2020 by Eddie N Gutierrez. E-Mail: enaguti1949@gmail.com