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Equation 89 · Part 2 · No Particle Without a Cosigner

Symbol a

Ddet(a, a+δa)  ≈  0.394 ∣δa∣a.D_{\rm det}(a,\, a+\delta a) \;\approx\; 0.394\, \frac{|\delta a|}{a}.
aa

What this part means

a is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

a is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

This is the same trick used to derive Wien’s displacement law: because u\,g(u) rises from zero, passes through a single interior maximum, and falls back to zero, the integral of the absolute value of its derivative over all u is exactly twice that maximum, with no need to evaluate the integral directly. Finding the maximum of u\,g(u) = 24\,u2u^2/(e2πue^{2\pi u}-1) means solving e2πu(1−πu)e^{2\pi u}(1-\pi u)=1 , the same…

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A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

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Sources cited in the article section

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