← All parts of this equation

Equation 85 · Part 1 · No Particle Without a Cosigner

Symbol u

u g(u)=24 u2/(e2πu−1)u\,g(u) = 24\,u^2/(e^{2\pi u}-1)
uu

What this part means

exactly twice that maximum.

Its job in the formula

u is part of the quantity the equation computes from the expression on the right.

Where the article explains it

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.

The passage around this formula

…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 class of transcendental equation that fixes the peak of a Planck spectrum weighted by an extra power of frequency.…

Read this part in the article →

Learn the underlying idea

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.

Open the illustrated variables: a letter stands for a value guide →

See this notation across published equations →

Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.