Derivation of number of quantum states

[TheCanadian]

Hi,

I recently saw a derivation that included:

[1] #CS = V_spatial * V_momentum

[2] #QS = #CS/h

(where # indicates it's the total number of the variable)

quantum states = QS; classical states = CS; h is Planck's constant

If possible, do you mind explaining or directing me to references that explain how [2] is derived and makes sense?

 

[DrClaude]

I recently saw a derivation

Where?