1. Jul 8, 2013

### iScience

when we do partial derivatives we use the curly ∂ to represent a partial change in something w/ respect to a partial change in something else. but say we have an integral with the integrand as a function of (x,y). why do we not use the curly ∂ as the differential when we integrate?

example..

why is it proper to write
∫2xydx

as opposed to this?

∫2xy∂x

2. Jul 8, 2013

### BucketOfFish

When integrating with respect to two or more variables which may vary independently, it is common to use a path integral, where each variable in the path is parametrized through a single common integration parameter. I have never seen a case where the notation you have indicated was necessary. However, it was a very interesting question and made me have to think for a while. Bravo!

3. Jul 8, 2013

### lurflurf

∂ is used sometimes