(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

u(f, T) = (8 pi h f^3)/(c^3 (e^(h f/ k T) - 1))

find an equation for the frequency, fmax, at which the energy density, u, is a maximum.

2. Relevant equations

C,h,pi, and k are constants.

3. The attempt at a solution

I took the derivative and set the equation equal to 0. My problem is I end up with a non-analytical equation. Instead I end up with the transcendental equation:

3(e^x - 1) - x e^x = 0 which I am not sure how to solve I know I must use Lambert's Product Law but I am unsure of how the W function works.

edit

as well x = (h f)/(k T)

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# Homework Help: Wien's Displacement Law

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