# I Differentiate two variables functions

1. Sep 28, 2017

### chimay

Hi,
I am dealing with an equality of the form:
$$f(x)=g(y,z)$$
and I need to compute $dx$.
Is the following relation correct?
$$dx={(\frac{\partial f}{\partial x})}^{-1}( \frac{\partial g}{\partial y}dy + \frac{\partial g}{\partial z}dz )$$

2. Sep 28, 2017

### andrewkirk

Yes, that's correct. Of course it breaks down at points where $\frac{\partial f}{\partial x}$ is zero, but maybe that's not in the domain of interest.

3. Sep 30, 2017

Thank you!