# Differential of a function vs differential forms

1. Dec 29, 2012

### Damidami

Hi,
I understand the concept of the differential of a (differentiable) function at a point as a linear transformation that "best" approximates the increment of the function there. So for example the differential of a function $f : D \subseteq \mathbb{R}^2 \to \mathbb{R}$ could maybe be $df = 8 dx + 9 dy$ at a given point, say $(2,3)$

But I wanted to know how this concept of differential is related to the integral concept of differential form, so for example $8dx + 9dy$ can be thoght as a differential form and be integrated over a curve. But the differential form usually varies from point to point so it could be more like $(3x+y^2)dx + (3xy) dy$, so I'm not sure if it also is been thought as a linear map, or should I think of these both concepts as completly different and unrelated things?

Thanks.

2. Dec 29, 2012

### Bacle2

I don't know if this is what you're looking for, but the differential of a differentiable function is a differentiable form, i.e., if f is a differentiable function, then df is a 1-form.