- Chapter 1
The same is valid for all higher derivatives such as
, i.e. the order of differentiation does not
Consider three variables x, y and z, each of which can be expressed as a function of the other two
variables, x=x(y,z), y=y(z,x) and z=z(x,y). (p,V and T in the ideal gas equation pV=NRT is an example).
Then the following identities are valid:
Consider a functions of x and y, f=f(x,y), other than z. Then: