Metallic MOS: Difference between revisions
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=== Why they cycle === | === Why they cycle === | ||
That is true of scale iterations where L - s > s. For the other type of scale iteration, where L - s < s, the result is simply reciprocated: | That is true of scale iterations where <span><math>L - s > s</math></span>. For the other type of scale iteration, where <span><math>L - s < s</math></span>, the result is simply reciprocated: | ||
<math>\ | <math> | ||
\begin{align} | |||
L’{:}s’ &= s{:}(L - s) \\ | |||
&= 1{:}(L - 1) \\ | |||
&= \frac{1}{L - 1} | |||
\end{align} | |||
</math> | </math> | ||
This alone would not suffice to explain how the <span><math>L{:}s</math></span> sequences lock into a cycle of isotopes. But here’s where the magic of the metallic means comes into play. <span><math>φ</math></span> has the property that | This alone would not suffice to explain how the <span><math>L{:}s</math></span> sequences lock into a cycle of isotopes. But here’s where the magic of the metallic means comes into play. <span><math>φ</math></span> has the property that | ||
<math>\qquad φ - 1 = 1 | <math>\qquad φ - 1 = \frac{1}{φ} | ||
</math> | </math> | ||
So, in the case of <span><math>φ</math></span>: | So, in the case of <span><math>φ</math></span>: | ||
<math>\ | <math> | ||
\begin{align} | |||
L’{:}s’ &= \frac{1}{L - 1} \\ | |||
&= \frac{1}{φ - 1} \\ | |||
&= \frac{1}{\frac{1}{φ}} \\ | |||
&= φ | |||
\end{align} | |||
</math> | </math> | ||
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A similar case is true for the silver mean, except we have to subtract 1 from it twice before the resulting value’s reciprocal is equal to the silver mean. | A similar case is true for the silver mean, except we have to subtract 1 from it twice before the resulting value’s reciprocal is equal to the silver mean. | ||
<math>\qquad δ_s - 1 - 1 = 1 | <math>\qquad δ_s - 1 - 1 = \frac{1}{δ_s} | ||
</math> | </math> | ||
And for the bronze ratio, we must subtract thrice: | And for the bronze ratio, we must subtract thrice: | ||
<math>\qquad | <math>\qquad δ_b - 1 - 1 - 1 = \frac{1}{δ_b} | ||
</math> | </math> | ||