Part D

Examine this set of Pythagorean triples from part C. Look for a pattern that is true for each triple regarding the difference between the three values that make up the triple. Describe this pattern. Then see if you can think of another Pythagorean triple that doesn't follow the pattern you just described and that can't be generated using the identity [tex]\(\left(x^2-1\right)^2+(2 x)^2=\left(x^2+1\right)^2\)[/tex]. Explain your findings.

\begin{tabular}{|c|c|}
\hline
[tex]$x$[/tex]-value & Pythagorean Triple \\
\hline
7 & [tex]$(14,48,50)$[/tex] \\
\hline
8 & [tex]$(16,63,65)$[/tex] \\
\hline
9 & [tex]$(18,80,82)$[/tex] \\
\hline
10 & [tex]$(20,99,101)$[/tex] \\
\hline
\end{tabular}



Answer :

To examine the Pythagorean triples presented for different [tex]\(x\)[/tex]-values and identify any patterns, let's look at the differences between the three values [tex]\(a\)[/tex], [tex]\(b\)[/tex], and [tex]\(c\)[/tex] in each triple.

Here are the given triples again for reference:

[tex]\[ \begin{array}{|c|c|} \hline x\text{-value} & \text{Pythagorean Triple} \\ \hline 7 & (14, 48, 50) \\ \hline 8 & (16, 63, 65) \\ \hline 9 & (18, 80, 82) \\ \hline 10 & (20, 99, 101) \\ \hline \end{array} \][/tex]

### Analyzing the Patterns
Let's look at each triple and examine the differences between [tex]\(a\)[/tex], [tex]\(b\)[/tex], and [tex]\(c\)[/tex]:

1. For [tex]\(x = 7\)[/tex]:
[tex]\[ (a, b, c) = (14, 48, 50) \][/tex]
Differences:
[tex]\[ b - a = 48 - 14 = 34 \][/tex]
[tex]\[ c - b = 50 - 48 = 2 \][/tex]

2. For [tex]\(x = 8\)[/tex]:
[tex]\[ (a, b, c) = (16, 63, 65) \][/tex]
Differences:
[tex]\[ b - a = 63 - 16 = 47 \][/tex]
[tex]\[ c - b = 65 - 63 = 2 \][/tex]

3. For [tex]\(x = 9\)[/tex]:
[tex]\[ (a, b, c) = (18, 80, 82) \][/tex]
Differences:
[tex]\[ b - a = 80 - 18 = 62 \][/tex]
[tex]\[ c - b = 82 - 80 = 2 \][/tex]

4. For [tex]\(x = 10\)[/tex]:
[tex]\[ (a, b, c) = (20, 99, 101) \][/tex]
Differences:
[tex]\[ b - a = 99 - 20 = 79 \][/tex]
[tex]\[ c - b = 101 - 99 = 2 \][/tex]

### Pattern Observed
From the differences calculated above, we observe the following patterns among the given Pythagorean triples:
- The difference [tex]\(b - a\)[/tex] increases as [tex]\(x\)[/tex] increases.
- The difference [tex]\(c - b\)[/tex] is consistently [tex]\(2\)[/tex] for all the triples.

### Generating Triples Using the Identity
The identity used to generate the triples is:
[tex]\[ (a, b, c) = (2x, x^2 - 1, x^2 + 1) \][/tex]

This consistently produces triples where:
[tex]\[ c - b = 2 \][/tex]

### Example of a Pythagorean Triple Not Fitting This Pattern
Let's consider a well-known Pythagorean triple that does not follow this pattern and cannot be generated using the given identity:

The triple [tex]\((3, 4, 5)\)[/tex]:

Here:
[tex]\[ b - a = 4 - 3 = 1 \][/tex]
[tex]\[ c - b = 5 - 4 = 1 \][/tex]

This triple [tex]\((3, 4, 5)\)[/tex] does not fit the pattern [tex]\(c - b = 2\)[/tex] and cannot be generated using the identity [tex]\((2x, x^2 - 1, x^2 + 1)\)[/tex], since the identity would produce distinct differences as observed from the given set of triples.

### Conclusion
Upon examining the given set of Pythagorean triples, we see a consistent pattern of the difference [tex]\(c - b = 2\)[/tex]. The classic Pythagorean triple [tex]\((3, 4, 5)\)[/tex], however, does not fit this pattern and cannot be generated using the identity [tex]\( (2x, x^2 - 1, x^2 + 1) \)[/tex].