Hey there. While studying the Single-particle Level Density, I encountered the example in the image below, referring to the One-dimensional Box problem. However, I do not understand what is it that he call's F(E), neither how does one go from that, to the density of states in Equation (3.64). http://imgur.com/cBRbFXz Can somebody hint me on how to reproduce this result? Thank you for your time.