## xyz density functions

Read through Eisberg & Resnick on the derivation fo the electron gas energy distribution of conduction electrons in a metal.  This book is really good, I’m glad I have it.

$n(E)N(E)dE = \frac{8 \pi V (2m^3)^{1/2}}{h^3} \frac{E^{1/2} dE}{e^{(E-E_F)/kT}+1}$

Now I also finally got clear on “density functions”, the meaning of the dE in a formula, and why they live to be integrated.