# Homework Help: Exact and Inexact Differential!

1. Feb 19, 2009

### FourierX

1. The problem statement, all variables and given/known data

Is (x2 -y)dx + xdy = dF an exact differential ?

dF = path dependant ( i.e. d has a line strikethrough it as h in planck's constant.)

2. Relevant equations

(x2 -y)dx + xdy = dF

3. The attempt at a solution

2. Feb 19, 2009

### tiny-tim

Hi FourierX!

Exact differential means that the left hand side is exactly d(something), for example y2cosxdx + 2ysinxdy is an exact differential because it is d(y2sinx)

3. Feb 19, 2009

### djeitnstine

Mdx + Ndy = f(x) is exact only when this condition is met $$\frac{\partial M}{\partial y} = \frac{\partial N}{\partial x}$$ (It has to be EXACTLY equal...no minus signs allowed etc..)