Metallic MOS: Difference between revisions
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First we’ll document some behavior of continued fractions. Then we’ll get into applications. | First we’ll document some behavior of continued fractions. Then we’ll get into applications. | ||
The metallic means are all irrational numbers. Therefore their continued fractions are infinite, with a periodic pattern at the end. An advantage of continued fractions over the decimal system is that we can easily determine whether a number is rational by whether a periodic pattern at the end is required. Decimals, on the other hand, sometimes require periodic patterns at the end even when the number is rational, such as 1/3 which is 0. | The metallic means are all irrational numbers. Therefore their continued fractions are infinite, with a periodic pattern at the end. An advantage of continued fractions over the decimal system is that we can easily determine whether a number is rational by whether a periodic pattern at the end is required. Decimals, on the other hand, sometimes require periodic patterns at the end even when the number is rational, such as 1/3 which is 0.<span style="text-decoration:overline">3</span>, or 1/7 which is 0.<span style="text-decoration:overline">142857</span>; as continued fractions these two values are, respectively, [0; 3] and [0; 7]. | ||
The golden mean has the continued fraction [1; | The golden mean has the continued fraction [1; <span style="text-decoration:overline">1</span>]. The larger a term in a continued fraction, the closer the approximation of the value at that point; by this conception of irrationality, the golden mean is sometimes said to be the most irrational number possible, eluding close approximation by any ratio as much as possible at every turn. | ||
The silver mean follows it closely with continued fraction [2; | The silver mean follows it closely with continued fraction [2; <span style="text-decoration:overline">2</span>], and the bronze mean with [3; <span style="text-decoration:overline">3</span>]. | ||
A handy way to quickly find the reciprocal of a number is to prepend its continued fraction with a 0. So, we can find the golden mean’s isotope 0.618034 is [0; | A handy way to quickly find the reciprocal of a number is to prepend its continued fraction with a 0. So, we can find the golden mean’s isotope 0.618034 is [0; <span style="text-decoration:overline">1</span>]. | ||
Actually any isotope’s continued fraction is found by simply depleting the initial term. For example, the silver mean’s isotopes are [1; | Actually any isotope’s continued fraction is found by simply depleting the initial term. For example, the silver mean’s isotopes are [1; <span style="text-decoration:overline">2</span>] and [0; <span style="text-decoration:overline">2</span>]. The initial term of a continued fraction, the one to the left of the semicolon, carries the same information as the digit of a decimal just to the left of the decimal point, i.e. any number starting with [0;] is between 0 and 1. | ||
The continued fraction for any abstract generator should start with 0, then, because it must be less than the period, which is 1 (if not less than 0.5, as we’ve been preferring, because of the generator complement effect). | The continued fraction for any abstract generator should start with 0, then, because it must be less than the period, which is 1 (if not less than 0.5, as we’ve been preferring, because of the generator complement effect). | ||
Noble generators start with other numbers but then settle on all 1’s; for example, our earlier example of 0.419821 is [0; 2, 2, | Noble generators start with other numbers but then settle on all 1’s; for example, our earlier example of 0.419821 is [0; 2, 2, <span style="text-decoration:overline">1</span>]. | ||
Crossing nobles with beyond golden cases results in continued fractions which can start with anything but eventually settle on all 2’s, 3’s, or n if we base our noble on the n<sup>th</sup> metallic mean. For example, our earlier example 0.226541 is [0; 4, | Crossing nobles with beyond golden cases results in continued fractions which can start with anything but eventually settle on all 2’s, 3’s, or n if we base our noble on the n<sup>th</sup> metallic mean. For example, our earlier example 0.226541 is [0; 4, <span style="text-decoration:overline">2</span>] | ||
=== Application: L:s sequences === | === Application: L:s sequences === | ||